{
  "id": "baseball",
  "title": "Baseball",
  "lang": "en",
  "source_lang": "en",
  "summary": "Baseball is a bat-and-ball team sport organized around pitching, batting, baserunning, and fielding, with extensive professional and international traditions.",
  "category": "society",
  "subcategory": "sports",
  "type": "concept",
  "aliases": [
    "Base ball",
    "hardball"
  ],
  "generated_at": "2026-10-13",
  "model": "pro/gpt-6.1-sol",
  "url": "https://aiwiki.page/en/baseball/",
  "translations": {
    "zh-Hans": {
      "url": "https://aiwiki.page/zh/baseball/",
      "json": "https://aiwiki.page/zh/baseball.json"
    }
  },
  "sections": [
    {
      "heading": "",
      "text": "Baseball is a bat-and-ball sport in which two teams alternate between batting and fielding. In its standard form, each team fields nine players, and a regulation game consists of nine innings. The batting team attempts to score runs by advancing runners around three bases and back to home plate, while the fielding team attempts to retire opposing players. Three outs end a team’s half-inning; the team with more runs at the conclusion wins. Its organization around outs rather than a fixed match clock distinguishes baseball from many other team sports. (mktg.mlbstatic.com)\n\nModern baseball developed from earlier bat-and-ball games and acquired its principal rules and institutions in the nineteenth-century United States. Long associated with the American “national pastime,” it also established substantial traditions in East Asia, the Caribbean, and other parts of the Americas. Its history encompasses professionalization, racial segregation and integration, women’s participation, and the movement of players and playing traditions across national borders. (loc.gov)\n\nBaseball combines individual contests between pitcher and batter with coordinated team defense and tactical decisions about advancing runners. Its detailed statistical record supports both historical comparison and quantitative analysis. Understanding the sport therefore involves its rules, playing skills, equipment and venues, alongside the leagues, international competitions, economic institutions, and cultural practices that sustain it. (mktg.mlbstatic.com)"
    },
    {
      "heading": "The Field, Equipment, and Playing Environment",
      "text": "The infield diamond is a square with sides of 90 feet (27.432 metres), marked by home plate and first, second, and third bases. Home plate is a five-sided white rubber slab, 17 inches across its front, with its rear point at the intersection of the foul lines. These lines extend through first and third bases toward the outfield boundary: the lines themselves belong to fair territory, as does the enclosed area extending to the fence; the areas outside them are foul territory. Foul territory remains part of the playing environment, rather than automatically being out of bounds. Rectangular batter’s boxes, each 6 feet long and 4 feet wide, flank home plate. (mktg.mlbstatic.com)\n\nThe pitcher’s rubber is a white rectangle measuring 24 by 6 inches, with its front edge 60 feet 6 inches (18.4404 metres) from the rear point of home plate. It stands on a mound 10 inches above home-plate level. These are standard adult dimensions, not universal youth specifications: Little League’s Major Division uses 60-foot base paths and a 46-foot pitching distance, while its Intermediate division uses 70-foot paths and a 50-foot pitching distance. (mktg.mlbstatic.com)\n\nA regulation ball consists of yarn wound around a small core of cork, rubber, or similar material, enclosed by two tightly stitched pieces of white horsehide or cowhide. Its prescribed weight is 5–5¼ ounces, approximately 142–149 grams, and its circumference is 9–9¼ inches, approximately 22.9–23.5 centimetres. The professional bat is normally a single piece of solid wood, no more than 42 inches long and 2.61 inches in diameter at its thickest point. Nonwooden bats are governed by competition-specific standards rather than the professional wooden-bat specification. Little League permits approved aluminum/alloy and composite bats, with certification requirements varying by division. (img.mlbstatic.com)\n\nFielders use leather gloves or mitts whose dimensions and webbing are regulated. Ordinary fielding gloves have separate finger sections; the catcher’s mitt has a different, rounded construction and is regulated separately from the first baseman’s mitt. Professional players must wear protective helmets when batting and running the bases; major-league batting helmets must have at least one ear flap, while minor-league helmets require two. Catchers must wear helmets and face masks while receiving pitches. Additional equipment includes chest protectors and shin guards; Little League also expressly requires a throat guard as part of the catcher’s protective equipment. (img.mlbstatic.com)\n\nUnlike the diamond, the outfield has no single prescribed shape or uniform fence height. The Official Baseball Rules specify minimum distances for newly constructed professional parks, but established parks can have markedly different boundaries. (mktg.mlbstatic.com) At Fenway Park in Boston, the left-field foul line measures 310 feet and the right-field line 302 feet; the Green Monster rises approximately 37 feet above left field. A ball’s distance alone therefore does not determine whether it clears a boundary: fence height and its location along the ball’s trajectory also matter. (img.mlbstatic.com)\n\nPlaying surfaces and overhead structures introduce further local differences. Arizona’s Chase Field changed to synthetic grass in 2019 and has a retractable roof; such enclosed environments differ from open-air grounds exposed directly to weather. (mlb.com) Park-specific ground rules define the treatment of unusual obstacles and openings. Under Tropicana Field’s published 2024 rules, a batted ball striking either lower catwalk over fair territory was a home run, whereas contact with an upper catwalk could leave the ball in play. These provisions distinguish physical contact with stadium structures from ordinary contact with the playing surface or outfield wall. (img.mlbstatic.com)"
    },
    {
      "heading": "Innings, Scoring, and the Progress of a Game",
      "text": "An inning comprises two turns at bat: the visiting team bats in the top, and the home team in the bottom. During each half-inning, the other team fields; three outs end the batting team’s turn. Outs reset to zero, and runners remaining on base do not carry over. The standard game lasts nine innings, subject to early completion, interruption, or extension for a tied score. The winner is determined by runs, not hits. (mktg.mlbstatic.com)\n\nA run requires a runner to touch first, second, third, and home in that order. A hit records a batter’s safe advance on a batted ball without an error or fielder’s choice; it need not produce a run. (mktg.mlbstatic.com) For example, starting with empty bases, batter A singles, batter B singles while A advances to third, and batter C singles while A touches home and B reaches second. This hypothetical sequence produces three hits but only one run, credited to A; B and C remain on base. Conversely, a player who reaches through an error can subsequently score a run. (mlb.com) Crossing home before the third out is not always sufficient: no run counts on a play whose third out is a force out or the batter-runner’s out before reaching first. (mktg.mlbstatic.com)\n\nIf the home team leads after the top of the ninth, the bottom half is unnecessary. A tie after nine innings leads to extra innings; the visitors must finish an inning ahead to win. (mktg.mlbstatic.com) A walk-off ends play when the home team takes the lead in the ninth or later. (mlb.com) On a game-ending home run over the fence, however, all eligible runners may complete their circuits and score. (mktg.mlbstatic.com) MLB introduced its regular-season automatic runner in 2020 and made the provision permanent in 2023. (mlb.com) Under the 2026 rules, each extra half-inning starts with a runner on second, normally the player immediately preceding the scheduled leadoff batter; postseason innings start with empty bases. (mktg.mlbstatic.com)\n\n“Regulation” also determines how interrupted games are treated. Five completed innings—or four and a half with the home team ahead—normally meet the threshold. (mlb.com) Under MLB’s 2026 rules, games stopped before that threshold, while tied, or during an incomplete inning in which the visitors have tied or taken the lead without a home-team reply are suspended. They resume at the stopping point rather than restart. Other called regulation games can end with a shortened result. A forfeit instead awards victory for specified violations, including refusal to continue or inability to field nine players. (mktg.mlbstatic.com)\n\nShorter formats and run-difference endings depend on the competition. Little League tournament rules in 2026 provide six scheduled innings for the younger divisions and seven for Intermediate, Junior, and Senior divisions. Their extra-inning runner starts on second in the seventh or eighth inning respectively. In six-inning divisions, a 15-run lead ends the contest after three innings, or two and a half if the home team leads; a 10-run lead ends it after four, or three and a half with the home team ahead. The visitors’ qualifying lead always requires a home-team batting opportunity. These provisions are often called mercy rules, although Little League uses “run rule.” Tournament ties and incomplete games are resumed, not accepted as final draws. (littleleague.org)"
    },
    {
      "heading": "Batting, Baserunning, and Ways of Making an Out",
      "text": "The strike zone is the space above home plate between the midpoint of the batter’s shoulders and the top of the uniform pants and the hollow below the kneecap, determined from the batter’s stance when preparing to swing. An un swung-at pitch passing through this space is a called strike; swinging and missing produces a swinging strike regardless of location. An untaken swing at a pitch outside the zone is a ball. Four balls award first base—a walk—while three strikes constitute a strikeout, subject to the uncaught-third-strike exception. An untouched foul ball ordinarily makes the ball dead and adds a strike only when fewer than two have been recorded; a foul bunt with two strikes retires the batter. A foul tip travels sharply and directly from the bat to the catcher and is legally caught: it counts as a strike, including strike three, and remains live. A hit-by-pitch awards first base when the batter is not swinging, the pitch is outside the zone, and the batter attempts to avoid it. (img.mlbstatic.com)\n\nA hit is classified by the bases earned through batting: a single reaches first, a double second, a triple third, and a home run completes the circuit. A fair ball clearing the outfield fence in flight normally produces a home run; an inside-the-park home run completes the circuit without clearing it. Reaching base through an error—defensive mishandling of a play achievable with ordinary effort—or a fielder’s choice is not a hit. For example, a grounder on which the shortstop retires the runner advancing from first at second, rather than throwing out the batter at first, produces a fielder’s choice. Additional advancement through a subsequent error does not increase a hit’s value. (content.mlb.com)\n\nA legally caught fair or foul fly ball retires the batter. A force out occurs when a runner must advance because the batter becomes a runner: the defense can retire that runner by holding the ball while touching the required base before arrival. With a runner on first, a grounder can therefore yield outs at second and first—a double play. A triple play retires three offensive players during one continuous action. Without a force, a fielder generally must tag the runner with the ball or the hand or glove holding it. After a caught fly, runners must “tag up”: remain on, or return to, their original bases before advancing after the ball is first touched. Missing a base or leaving too early permits a defensive appeal, ordinarily made before the next pitch or play. (content.mlb.com)\n\nRunners can advance while the ball remains live, including by stealing; unsuccessful attempts are recorded as caught stealing under the scoring rules. A pickoff is a throw intended to retire a runner away from a base. A wild pitch is beyond the catcher’s ability to control with ordinary effort; a passed ball is a catchable pitch the catcher fails to hold, allowing advancement. Such advancement is not automatically a stolen base. When a tag is attempted, the runner’s base path becomes the straight line from the runner’s position to the intended base; deviating more than three feet (0.9144 metres) to evade that tag causes an out. (mktg.mlbstatic.com)\n\nThe infield-fly rule prevents defenders from deliberately allowing a routine fly to fall and then obtaining force outs. With fewer than two outs and runners on first and second, or the bases loaded, a fair fly catchable by an infielder with ordinary effort—not a line drive or bunt—retires the batter when declared. The ball remains live; runners must tag up if it is caught. On an uncaught third strike, the batter may attempt first if first was unoccupied at the pitch or there were two outs; the strikeout is still recorded. (mktg.mlbstatic.com)\n\nInterference includes offensive actions hindering a defender’s protected opportunity to field the ball and can produce an out and a dead ball. Obstruction occurs when a defender neither possessing nor fielding the ball impedes a runner. Under the 2026 Official Baseball Rules, obstruction against a runner being played upon stops play immediately; otherwise play continues before remedial base awards. Uncaught foul balls, qualifying hit-by-pitches, balls entering out-of-play areas, and an umpire’s call of “Time” also make the ball dead, preventing ordinary advancement until play resumes. (mktg.mlbstatic.com)"
    },
    {
      "heading": "Player Positions, Lineups, and Team Personnel",
      "text": "The nine defensive positions have conventional scorekeeping numbers: pitcher (1), catcher (2), first baseman (3), second baseman (4), third baseman (5), shortstop (6), left fielder (7), center fielder (8), and right fielder (9). These identify positions, not jersey numbers or places in the batting order. The three basemen and shortstop constitute the infield; left, center, and right field constitute the outfield, with directions viewed from home plate. Pitcher and catcher form the battery. Thus, a “6–4–3” double play describes the shortstop throwing to the second baseman, who then throws to the first baseman—not three particular players. (littleleague.org)\n\nBefore play, each manager submits a starting lineup identifying defensive assignments and the nine-place batting order. Batters follow that sequence repeatedly: after the ninth place comes the first, and a new inning does not restart the order. Defensive positions do not determine batting places. Under the 2026 Official Baseball Rules, a substitute inherits the replaced player’s batting-order position, and a player removed from the game cannot re-enter. A pinch hitter replaces a batter; a pinch runner replaces a runner already on base. Neither is merely a temporary stand-in: the replacement remains in the lineup unless subsequently substituted for. Changing defensive assignments among players already in the game does not itself change their batting order. (mktg.mlbstatic.com)\n\nThe designated hitter (DH) bats instead of the pitcher without becoming a tenth defender. The American League introduced the rule in 1973, and the National League adopted it permanently in 2022. (mlb.com) A replacement hitter or runner for the DH becomes the new DH. Ordinarily, moving the DH into a defensive position ends the team’s DH privilege for that game. Rule 5.11(b), however, treats a starting pitcher simultaneously listed as DH as two separate lineup functions: replacement as pitcher need not remove that player as DH, and replacement as DH need not end the pitching appearance. This arrangement permits the two duties to be substituted independently. (mktg.mlbstatic.com)\n\nPitching labels describe assignments within position 1, not additional defensive positions. The starter pitches first; relief pitchers enter afterward, and a closer specializes in protecting late leads, usually in the ninth inning. (mktg.mlbstatic.com) A utility player covers multiple defensive positions; Ben Zobrist exemplified this role with Tampa Bay. (mlb.com) A two-way player combines pitching with regular batting duties. Shohei Ohtani’s dual assignment illustrates the distinction between a player’s role and the position occupied during a particular play. (mlb.com)\n\nThe field manager selects lineups and directs substitutions and pitching changes. The bench coach advises the manager and commonly takes charge when the manager is unavailable. (mlb.com) First-base coaches assist runners with pickoff awareness and baserunning; third-base coaches relay signals and direct runners to advance or hold. (mlb.com) Pitching coaches supervise mechanics and preparation; hitting coaches work on swing mechanics, plate discipline, and preparation for opposing pitchers. (mlb.com) These are coaching responsibilities rather than playing positions, even when a coach has previously played professionally.\n\nPersonnel beyond the dugout perform separate evaluative and operational functions. Amateur scouts assess prospective recruits, professional scouts evaluate players already in professional leagues, and advance scouts study upcoming opponents. Their reports inform player acquisition and game preparation rather than conferring authority to make substitutions. (mlb.com) Clubhouse managers and attendants maintain uniforms and equipment, organize supplies, and prepare facilities for players and coaches. Equipment responsibilities extend to packing and transporting bats, balls, helmets, and uniforms between facilities; travel coordination may be assigned separately or combined with clubhouse duties. (milb.com)"
    },
    {
      "heading": "Pitching, Hitting, and Defensive Skills",
      "text": "Pitching delivery coordinates the legs, trunk, shoulder, arm, and hand: the pitcher moves toward home plate, lands the stride foot, rotates the body, accelerates the throwing arm, and follows through after release. The release point has vertical, horizontal, and forward components; different trunk tilts and arm slots produce overhand, three-quarter, sidearm, and submarine deliveries. These differences change the angle from which a batter sees the ball. Velocity describes ball speed, whereas control means throwing strikes and command means placing pitches at intended locations, including deliberately outside the strike zone. Repeating the delivery helps maintain a consistent release and location. (ericcressey.com)\n\nPitch families combine differences in grip, speed, spin, and movement. A four-seam fastball is generally a pitcher’s fastest, straightest offering; a cutter adds movement toward the glove side. Breaking balls include curveballs and sliders, with sliders generally faster and less sweeping than curveballs. A changeup resembles a fastball’s delivery but arrives more slowly, disrupting the batter’s timing. These labels describe families rather than identical trajectories: two pitchers’ pitches of the same name can differ substantially. (mlb.com)\n\nBatting begins from a balanced stance with flexed knees and a position that permits the hitter to see the pitcher and cover the plate. Preparatory movement and a stride establish timing; coordinated hip and upper-body rotation accelerate the bat, followed by extension and follow-through. Strike-zone judgment combines recognizing location with deciding whether a pitch can be struck effectively. Contact-oriented hitting emphasizes meeting the ball consistently, while power hitting emphasizes producing high outgoing speed and trajectories capable of reaching the gaps or clearing a fence; these skills are not mutually exclusive. Bunting replaces the full swing with a presented bat whose angle directs the ball, while grip and controlled contact limit its speed. (nccp.baseball.ca)\n\nCatchers receive pitches from a crouch and communicate pitch choices through concealed hand signals. (mlb.com) Receiving requires securing the ball, while blocking a pitch in the dirt requires moving the body into its path and keeping the rebound nearby, rather than relying solely on the mitt. Catchers also communicate outs, runner locations, and developing plays to teammates. (littleleague.org) Throws to bases combine rapid footwork, a glove-to-hand transfer, arm speed, and accuracy; strength alone does not determine their effectiveness. (mlb.com)\n\nFielding connects the catch to the next throw. Infielders approach ground balls with bent knees and an open glove, then transfer the ball and organize their feet toward the target. Outfielders read the batted ball, move toward its interception point, and raise the glove for the catch rather than running throughout with an extended arm. When time permits, their approach carries momentum toward the subsequent throw. Long returns can use a relay player to catch and throw again; cutoff players intercept or redirect returns when another base becomes the appropriate target. Players not directly involved back up the receiver or ball handler, limiting advancement after a missed catch or inaccurate throw. (champlainvalleylittleleague.org)\n\nBall flight reflects gravity, aerodynamic drag, and spin-dependent forces, notably the Magnus effect. Backspin supplies an upward force that reduces a fastball’s drop; topspin contributes downward movement, while a tilted spin axis can produce sideways movement. Alan M. Nathan and colleagues’ experiment, reported in a 2006 preprint, tracked 22 balls at 50–110 miles per hour and 1,500–4,500 revolutions per minute to quantify aerodynamic lift. (arxiv.org) At impact, the bat transfers momentum to the ball, but the collision is not perfectly elastic: deformation and bat vibration affect outgoing speed. Nathan’s 2000 collision model incorporated wooden-bat vibration; experiments by Rod Cross and Nathan published in 2006 showed that oblique contact involves tangential deformation, not simply a rigid ball rolling off the bat. Contact geometry therefore helps determine both launch direction and outgoing spin. (baseball.physics.illinois.edu)"
    },
    {
      "heading": "Tactical Decisions and Game Management",
      "text": "Pitch selection combines a pitcher’s available repertoire with the batter’s strengths, the count, and the consequences of contact. Sequencing changes speed, location, and movement across successive pitches: a fastball followed by a slower changeup can disrupt timing, while repeating a pitch may exploit a weakness but become predictable. At two strikes, a pitcher may seek a chase outside the strike zone; at three balls, another miss risks a walk. These are conditional choices rather than fixed sequences. Platoon advantage generally favors batters facing opposite-handed pitchers, influencing both starting lineups and substitutions. A 2015 study of MLB pitch sequences explicitly distinguished selection patterns by count and handedness, illustrating why pitch predictability must be assessed within the plate appearance’s changing context. (mdpi-res.com)\n\nDefensive positioning trades coverage against the speed required to complete a particular play. With a runner on first and fewer than two outs, double-play depth brings the middle infielders somewhat closer to second base and shallower, shortening their routes to receive a throw. An infield-in alignment instead prioritizes a throw home against a runner on third, sacrificing reaction time and coverage behind the fielders. Outfielders can shade toward anticipated contact, move deeper against extra-base hits, or play shallower when a throw home is paramount. Under MLB’s 2026 rules, at pitch release at least four defenders other than pitcher and catcher must have both feet inside the outer boundary of the infield dirt, with at least two entirely on each side of second base. These restrictions limit, rather than eliminate, tactical repositioning. (cdn1.sportngin.com)\n\nOffensive plays differ in whether they deliberately exchange an out for advancement. A sacrifice bunt attempts that exchange directly; a sacrifice fly describes a scoring outcome from a caught fly rather than a guaranteed play that can simply be ordered. On a hit-and-run, the runner breaks with the pitch and the batter attempts contact, potentially exploiting the gap opened by an infielder covering second; a miss exposes the runner, while a caught line drive can produce a double play. A safety squeeze delays the runner’s commitment from third until the bunt is down, whereas a suicide squeeze commits the runner before contact. An intentional walk avoids the current batter but supplies another baserunner. For example, walking a powerful hitter with second occupied and first open creates force-play possibilities, yet also increases the damage possible from the next hit or walk. (cdn1.sportngin.com)\n\nThe value of advancement depends on score and inning, not merely distance from home. In a hypothetical tied ninth inning, a successful bunt moving a runner from second to third with one out makes certain fly balls and ground balls potential winning plays; a failed bunt or strikeout leaves a less favorable situation. Earlier in a game, surrendering an out may instead curtail a multi-run inning. Stolen-base decisions likewise compare outcomes. In an illustrative expected-value model, suppose success adds 0.20 expected runs and failure costs 0.50 relative to holding position. With success probability \\(p\\), the net change is \\(0.20p-0.50(1-p)\\), positive only above approximately 71.4 percent. These are assumed values, not measured league averages; actual thresholds vary with the runners, outs, hitters, and objective of scoring one run versus several. (blogs.fangraphs.com)\n\nLineup construction places productive hitters early to obtain more plate appearances. Bench deployment can supply a favorable hitting matchup, faster runner, or stronger defender, but MLB substitutions are irreversible: a removed player cannot re-enter. Bullpen choices similarly balance the immediate matchup against subsequent hitters and remaining pitching resources. Repeated exposure matters: teams may replace a starter before another encounter with the top of the order. MLB’s three-batter minimum, introduced in 2020 and retained in the 2026 rules, normally requires a pitcher to complete three batters’ appearances or finish the half-inning, subject to injury or illness exceptions. Consequently, selecting a reliever for one left-handed hitter also requires considering the right-handed hitters who may follow. (mlb.com)"
    },
    {
      "heading": "Umpiring, Rulebooks, and Changes to Play",
      "text": "Under the 2026 Official Baseball Rules (OBR), the plate umpire directs the game and calls balls and strikes; field umpires exercise jurisdiction over assigned plays and share authority to enforce rules and maintain discipline. A disputed rules interpretation differs from a judgment call: a manager may ask the responsible umpire to reconsider whether a rule was applied correctly, whereas judgments ordinarily stand unless an authorized consultation or review procedure changes them. A defensive appeal concerning a missed base or failure to retouch is a prescribed play, not simply an argument against an umpire’s decision. Umpires may eject participants for misconduct; an ejected manager or player must leave the field and take no further part in the game. (mktg.mlbstatic.com)\n\nThe OBR are not a universal code for every competition. United States high-school baseball uses National Federation of State High School Associations rules, college baseball has an NCAA rulebook, and youth organizations publish their own regulations. One consequential difference concerns substitutions: OBR Rule 5.10(d) prohibits a removed player from re-entering, while an NFHS interpretation published in 2025 confirms that a withdrawn starter may return, including as a pitcher. Little League’s regular-season Rule 3.03 permits a starter to return to the same batting-order position after the substitute has satisfied mandatory-play requirements; tournament provisions can differ. International play likewise has separately dated WBSC rules and Baseball World Cup tournament regulations, rather than automatically incorporating every MLB innovation. (mktg.mlbstatic.com)\n\nChanges to pitching and substitution rules have altered the balance between offense and defense. Overhand pitching became permissible in 1884; in 1893, a pitching plate replaced the pitcher’s box at 60 feet 6 inches from home. (mlb.com) The American League adopted the designated hitter in 1973, with Ron Blomberg becoming its first user; permanent adoption in the National League followed in 2022. (mlb.com) A further 2022 amendment allowed a starting pitcher listed separately as pitcher and designated hitter to continue in either capacity after relinquishing the other. (mlb.com) MLB introduced its three-batter minimum in 2020. (mlb.com) Under the 2026 rule, pitchers must complete three consecutive batters’ plate appearances or finish the half-inning, unless incapacitated by injury or illness. (mktg.mlbstatic.com)\n\nMLB introduced limited home-run video review on August 28, 2008, then expanded review to additional categories in 2014. (mlb.com) Managers gained challenges for specified plays, including tag and force plays, rather than an unrestricted right to review every decision. (mlb.com) Replay umpires assess video centrally in New York City, separating the on-field decision from the review process. (mlb.com) Thus, an ordinary base-running appeal, a manager’s replay challenge, and a request for clarification of a rule are distinct procedures.\n\nMLB’s 2023 changes introduced pitch timing and restrictions on defensive positioning after minor-league testing. (mlb.com) The timer initially allowed 15 seconds with empty bases and 20 with runners aboard; the latter became 18 seconds in 2024. (img.mlbstatic.com) Pitcher violations produce an automatic ball; batters must be alert with eight seconds remaining or receive an automatic strike. (mlb.com) Pitchers ordinarily receive two disengagements per plate appearance; an unsuccessful third pickoff attempt advances the runner. (mlb.com) Defensive restrictions require four infielders within the infield boundary and two on each side of second base at the prescribed moments. (mlb.com)\n\nThe Automated Ball–Strike System (ABS) followed a separate experimental path: selected Triple-A parks used it from 2022, all Triple-A parks from 2023, and MLB tested challenges during 2025 spring training and the All-Star Game. MLB adopted the challenge format for 2026, retaining human umpires’ initial calls rather than automating every pitch. Only the batter, pitcher, or catcher may immediately challenge, without assistance from others. Each team starts with two challenges and retains successful ones; a team entering an extra inning with none receives one. Twelve tracking cameras locate the pitch against a two-dimensional, 17-inch-wide zone at the middle of home plate, extending from 27% to 53.5% of the batter’s certified height. Any overlap between ball and zone constitutes a strike. These implementation dates distinguish earlier trials from an adopted major-league procedure. (img.mlbstatic.com)"
    },
    {
      "heading": "Origins and Nineteenth-Century Codification",
      "text": "A documented British antecedent appears in John Newbery’s A Little Pretty Pocket-Book, first published in England in 1744, which included a rhyme headed “Base-Ball.” Its American edition, printed by Isaiah Thomas in Worcester, Massachusetts, in 1787, depicted three posts serving as bases and described a player striking the ball and running home. This evidence establishes the name and a recognizable batting-and-running activity before nineteenth-century American codification, not the complete modern game. Baseball developed within a broader family of British and North American bat-and-ball games; early American forms, often called town ball, differed between communities rather than following a single inherited rulebook. (loc.gov)\n\nThe regional alternatives involved substantially different structures of play. The New York game distinguished fair from foul territory, required three outs to retire a side, and prohibited retiring runners by throwing the ball at them. By contrast, the Massachusetts game, codified by ten clubs meeting in Dedham on May 13, 1858, allowed this practice, known as “soaking,” and ended a side’s batting turn after one out. Teams contained 10–14 players, the striker stood between the home and first-base positions, and the thrower delivered from 35 feet away. The association prescribed victory at 100 tallies, or runs, rather than after a fixed number of innings. These were competing baseball codes, not merely local interpretations of already settled rules. (blogs.loc.gov)\n\nThe Knickerbocker Base Ball Club, organized in New York City in 1845, helped formalize the New York version. Its rules provided for three-out turns, fair and foul balls, and tagging rather than soaking; they also permitted an out when a batted ball was caught on its first bounce. Games ordinarily continued until a side reached 21 “aces,” with equal turns at bat. Alexander Cartwright was associated with the club’s organization and rules, but their adoption was a stage in collective codification, not evidence that he invented baseball. On June 19, 1846, at Elysian Fields in Hoboken, New Jersey, the New York Club defeated the Knickerbockers 23–1. This documented, prearranged match became a historical landmark, although it followed earlier baseball activity and cannot establish the sport’s first-ever game. (blogs.loc.gov)\n\nInterclub competition made common regulations increasingly necessary. In 1854, the Knickerbockers, Gothams, and Eagles reconciled differences in their match rules. A larger convention met on January 22 and February 25, 1857, with sixteen clubs represented across its sessions. The resulting code established nine players per side, 90-foot base paths, a pitching distance of 45 feet, and nine-inning games. A seven-inning proposal was amended to nine; replacing the 21-run target made game duration less dependent on scoring. In 1858, clubs established the National Association of Base Ball Players as a continuing organization for the New York code. Its initially metropolitan membership and ambitions for national adoption should be distinguished from universal authority over all existing forms of baseball. (sabr.org)\n\nStandardization spread through club formation, negotiated matches, and printed instructions. Cheap pocket-sized guides enabled clubs outside the original New York network to reproduce a common code, while newspapers such as the New York Clipper published match reports and explanations by writers including Henry Chadwick. Adoption remained uneven: Massachusetts-rule clubs continued playing while New York-rule clubs appeared in the same region. A September 9, 1858, match between Boston’s Tri-Mountain Club and Portland demonstrated the New York game in New England; by September 1859, thirteen Massachusetts clubs were using those rules. The New York code displaced its regional competitors during the following decade, rather than through a single founding decree. (blogs.loc.gov)\n\nThe Abner Doubleday account arose much later. The Mills Commission, appointed in 1905, relied prominently on Abner Graves’s retrospective claim that Doubleday devised baseball in Cooperstown in 1839. Its report dated December 30, 1907, accepted that attribution. Doubleday, however, was a West Point cadet in 1839, and the account is not supported as a documented invention. The story nevertheless shaped commemoration: the National Baseball Hall of Fame opened in Cooperstown on June 12, 1939, during celebrations of baseball’s supposed centennial. That ceremony and Doubleday Field belong to the history of baseball’s public memory, not evidence overriding the earlier printed references and records of gradual codification. (baseballhall.org)"
    },
    {
      "heading": "Professionalization and Major Historical Eras",
      "text": "The Cincinnati Red Stockings of 1869, organized under Harry Wright, made salaried employment explicit across an entire playing roster rather than inventing payment to individual players. Their touring schedule demonstrated the commercial possibilities of professional competition. The National Association of Professional Base Ball Players, established in 1871, provided an early professional league but lasted only through 1875. On February 2, 1876, Chicago club owner William Hulbert helped establish the National League: an organization of clubs with defined membership, standard contracts, and stronger central authority. This shifted league governance toward owners and institutional continuity rather than a relatively open association of competing teams. (baseballhall.org)\n\nThe American League began competing as a major league in 1901, challenging the National League for players and audiences. Their 1903 settlement ended the immediate interleague struggle and established mutual recognition within a coordinated professional structure. That autumn, the Boston Americans defeated the Pittsburgh Pirates five games to three in the first modern World Series, a best-of-nine contest arranged between the clubs. Meanwhile, minor-league executives had formed the National Association of Professional Baseball Leagues on September 5, 1901. These initially independent circuits were not yet synonymous with developmental affiliates. During the 1920s and early 1930s, Branch Rickey’s St. Louis Cardinals expanded ownership of minor-league clubs into a farm system, developing players internally rather than relying principally on purchasing established talent; other organizations adopted the model. (baseballhall.org)\n\nThe “dead-ball” period, conventionally dated approximately 1900–1920, featured low scoring, relatively few home runs, and greater reliance on contact hitting and baserunning. Its transition into the live-ball era involved several changes rather than one technological breakthrough. Restrictions on doctored pitches and the introduction of clean replacement balls reduced advantages pitchers had obtained from discolored or altered baseballs. The 1920 spitball prohibition ultimately included exemptions for 17 established practitioners, so the change was not immediate or universal. Babe Ruth supplied the most conspicuous example of the new power-hitting approach: after hitting 29 home runs for Boston in 1919, he hit 54 for the New York Yankees in 1920 and 59 in 1921. His performances attracted national attention and helped make home-run hitting a central public spectacle. (baseball-reference.com)\n\nLighting and broadcasting changed when and where professional baseball could be followed. On May 24, 1935, Cincinnati’s Crosley Field hosted the first major-league night game, allowing spectators to attend after daytime work. Radio had already extended access beyond ballparks: Harold Arlin broadcast a Pittsburgh–Philadelphia game over KDKA on August 5, 1921, and all 16 major-league clubs had radio coverage by 1939. On August 26, 1939, NBC televised Cincinnati playing Brooklyn at Ebbets Field. World War II then disrupted playing personnel as stars including Bob Feller, Joe DiMaggio, and Ted Williams entered military service. President Franklin Roosevelt’s January 15, 1942, “Green Light Letter” supported continuing baseball for recreation, but did not prevent the substantial wartime loss of experienced players. (baseballhall.org)\n\nMajor-league geography subsequently expanded beyond its northeastern and midwestern concentration, although regional professional leagues had long operated elsewhere. The Pacific Coast League, founded in 1903, sustained substantial western competition before the Brooklyn Dodgers moved to Los Angeles and the New York Giants to San Francisco for the 1958 season. Relocation transferred existing franchises; expansion created additional ones. Expansion waves in 1961–1962, 1969, 1977, 1993, and 1998 increased the major-league total from 16 to 30 clubs and introduced markets including Houston, Montreal, Toronto, Denver, and Phoenix. (baseballhall.org)\n\nLater professional development combined broader international recruitment with increasingly systematic player evaluation. On 2024 Opening Day rosters and inactive lists, 27.8% of MLB players were born outside the 50 United States. Statistical approaches also influenced recruitment: Billy Beane’s Oakland organization used quantitative evaluation prominently in its 2002 draft, selecting college players with its first 17 picks. These developments connected team building more closely to international talent pools and statistical analysis, without making either recruitment or scouting exclusively numerical. (mlb.com)"
    },
    {
      "heading": "Racial Exclusion, Negro Leagues, and Integration",
      "text": "Black participation in nineteenth-century professional baseball preceded the establishment of segregated leagues. Bud Fowler played alongside white professionals beginning in 1878, moving between clubs as racial opposition restricted his opportunities. Moses Fleetwood Walker caught for the Toledo Blue Stockings in the American Association, then a major league, in 1884. Exclusion subsequently hardened through club decisions, player resistance, and restrictions on contracts rather than a single universally published rule. On July 14, 1887, the International League voted against signing additional Black players while allowing existing contracts to stand. Such measures consolidated the “color line” that excluded openly acknowledged Black players from the American and National Leagues until 1947. (baseballhall.org)\n\nBlack professional baseball nevertheless developed through independent clubs, touring teams, and eventually organized Negro leagues. Barnstorming—traveling to play locally arranged games—provided employment and revenue outside regular league schedules. On February 13, 1920, pitcher, manager, and Chicago American Giants owner Andrew “Rube” Foster brought club owners together in Kansas City to establish the Negro National League, becoming its first president. League organization provided a framework for scheduled competition, although access to ballparks remained uneven: most clubs leased grounds, and touring continued alongside league play. Black baseball therefore comprised overlapping league and independent operations, not a single uninterrupted organization. (baseballhall.org)\n\nSatchel Paige and Josh Gibson exemplified the talent sustained by these institutions. Paige’s pitching career combined Negro league competition with extensive touring, and he later joined Cleveland’s American League club in 1948. Gibson, a catcher associated particularly with the Pittsburgh Crawfords and Homestead Grays, supplied exceptional power hitting as well as defensive skill; he died in January 1947 without playing in the American or National League. Integration opened opportunities for players but weakened the institutions that had employed them. The departure of stars and diversion of paying audiences contributed to the Negro National League’s collapse after 1948, while other Black clubs continued operating. (baseballhall.org)\n\nJackie Robinson entered the Dodgers’ organization under executive Branch Rickey, playing for its Montreal affiliate in 1946 before debuting at first base for Brooklyn on April 15, 1947. His appearance ended the National League’s twentieth-century exclusion of Black players; it did not mark the beginning of Black professional baseball. Larry Doby, recruited from the Newark Eagles, made his Cleveland debut on July 5, 1947, integrating the American League. Both encountered racial hostility from participants and spectators. Desegregation proceeded club by club: the Boston Red Sox became the last of the sixteen existing American and National League franchises to field a Black player when Pumpsie Green appeared in 1959. Roster integration also did not immediately eliminate segregated spectator facilities in southern minor-league parks. (baseballhall.org)\n\nLatino players’ opportunities depended partly on how American clubs classified their ancestry and skin color. Washington’s recruitment in Cuba, for example, explicitly favored light-skinned players before integration. Afro-Cuban Minnie Miñoso played for the New York Cubans from 1946 to 1948, debuted with Cleveland on April 19, 1949, and became the Chicago White Sox’s first Black player in 1951. Roberto Clemente’s route from Puerto Rico differed: he played for Santurce, entered the Dodgers’ organization, and reached Pittsburgh in 1955 after selection in the Rule 5 draft. Clemente subsequently spoke publicly about the treatment of Latino players. These careers distinguish national origin and language from the racial classifications governing access to particular clubs. (baseballhall.org)\n\nHistorical research has also changed official statistical coverage. MLB recognized seven Negro leagues from 1920–1948 as major leagues in December 2020. On May 29, 2024, statistics for over 2,300 Negro league players entered MLB’s historical database. The recognized competitions were the two Negro National Leagues, Eastern Colored League, American Negro League, East-West League, the Negro Southern League’s 1932 season, and Negro American League through 1948; barnstorming exhibitions were excluded. Researchers Gary Ashwill and Kevin Johnson helped assemble the Seamheads database underpinning this reconstruction. Incomplete surviving records leave totals open to revision. The boundary of MLB recognition is distinct from broader historical assessment: in June 2024, a SABR committee identified 43 independent Black teams and the 1949–1950 Negro American League as major-league caliber. (sabr.org)"
    },
    {
      "heading": "International Diffusion and Regional Traditions",
      "text": "In Cuba, students returning from the United States brought baseball home during the 1860s, making overseas education an important transmission route. Esteban Bellán’s career illustrates movement in both directions: educated in the United States, he played for the Troy Haymakers in the National Association in 1871, before returning to Cuban baseball. Cuban migrants subsequently helped carry the game elsewhere in the Caribbean. These connections preceded several American military interventions; baseball’s expansion therefore cannot be explained solely as an export of United States occupation or professional leagues. (baseballhall.org)\n\nIn the Dominican Republic, Cuban sugar entrepreneurs introduced baseball by the 1870s. Plantation games during seasonal pauses in production developed into company teams sponsored by sugar, rum, and fruit businesses. West Indian migrant workers, some from cricket-playing communities, joined this developing baseball environment in towns such as La Romana and San Pedro de Macorís. During the United States occupation of 1916–1924, Dominican clubs also played visiting Marines, adding military contact to an already established commercial and migratory network. The country later became both a destination for foreign professionals and a source of players abroad: Satchel Paige and Josh Gibson played there in 1937, while subsequent recruitment linked Dominican development increasingly to American clubs. (origins.osu.edu)\n\nIn Japan, the conventional institutional starting point is American teacher Horace Wilson’s introduction of baseball to students at Kaisei Gakko in 1872. Schools and universities sustained the game, but exchange was not exclusively west-to-east: Waseda University toured the United States in 1905. The American tour featuring Babe Ruth in 1934 comprised 22 games in 12 Japanese cities. (baseballhall.org) Korea’s institutional history followed a different route. Philip Gillett taught baseball to Seoul YMCA members in 1905; school, university, and company teams subsequently provided foundations for South Korean baseball before professional competition began in 1982. (onlinemuseum.koreabaseball.com) In Taiwan, baseball developed through Japanese colonial schooling. The Kagi Agricultural and Forestry School team, known as Kano, included Japanese, Han Taiwanese, and Indigenous players and finished second at Japan’s national school championship in 1931. Its achievement widened local identification with a sport initially associated chiefly with Japanese participants. (digitalarchives.tw)\n\nOther Latin American traditions developed distinct institutions and connections. In Puerto Rico, winter baseball became a meeting point for local talent and visiting professionals: Roberto Clemente’s performances with Santurce attracted major-league scouts before he signed with Brooklyn in February 1954. (baseballhall.org) In Venezuela, victory over Cuba in the deciding game of the 1941 Amateur World Series became an important national baseball landmark. (museodebeisbol.com) In Mexico, employees of American businesses helped spread the sport during the late nineteenth century; Alejandro Aguilar Reyes and Ernesto Carmona founded the Mexican League in 1925. Mexican clubs also recruited Black American players excluded from the American major leagues. (baseballhall.org) Regional exchange was visible at the inaugural Caribbean Series in Havana in February 1949: only Venezuela’s representative fielded an entirely domestic roster, while the Cuban, Panamanian, and Puerto Rican entrants included American players. (baseballhall.org)\n\nCanada had its own early bat-and-ball traditions: an eyewitness’s later account described a game at Beachville, Ontario, on June 4, 1838, rather than a simple adoption of subsequently standardized American rules. (beachvilledistrictmuseum.com) In Australia, competitive games were played in Sydney in 1878, before A. G. Spalding’s visiting American teams toured in 1888–1889. Tour organizer Harry Simpson remained afterward and helped establish clubs in several cities. (baseball.com.au) In Europe, returning travelers and military personnel provided different routes: teacher J. C. G. Grasé introduced baseball to the Netherlands after visiting the United States in 1911; American soldiers encouraged its growth in Italy during World War II. (mlb.com)\n\nLater exchanges also carried locally developed players and practices abroad. Masanori Murakami reached the San Francisco Giants in 1964 through an arrangement involving Japan’s Nankai Hawks, and returned to Japan for 1966; Ichiro Suzuki moved from Japanese professional baseball to Seattle in 2001. (baseballhall.org) Spectator practices likewise acquired local forms rather than reproducing an identical American model. South Korean baseball, for example, developed organized cheering sections, coordinated chants, and individual songs for batters, integrating the imported game into a distinctive participatory ballpark environment. (mlb.com)"
    },
    {
      "heading": "Professional Leagues and Club Competition",
      "text": "Major League Baseball (MLB) comprises 30 clubs in the United States and Canada, divided equally between the American and National Leagues; each league has East, Central, and West divisions of five clubs. The 2025 schedule assigned each club 162 regular-season games. Under the postseason structure introduced in 2022 and retained in 2026, each league supplies three division winners and three wild-card teams, selected from the remaining clubs by record. The two highest-seeded division winners receive first-round byes. Other qualifiers play best-of-three Wild Card Series, followed by best-of-five Division Series and best-of-seven League Championship Series. The two league champions contest the best-of-seven World Series—an MLB championship, rather than a tournament open to champions of other professional leagues. (en.wikipedia.org)\n\nMLB’s affiliated Minor League Baseball system serves player development as well as local club competition. The restructuring implemented in 2021 established 120 full-season affiliates: each MLB organization supplies players and coaching staffs to one club at each of four ascending levels, Single-A, High-A, Double-A, and Triple-A. Rookie-level leagues provide additional entry points. Players receive organizational assignments rather than earning promotion for their club through league standings; affiliates nevertheless compete for their own championships. Recruitment includes the amateur draft and international signings. Independent leagues operate outside these club affiliations: MLB’s four designated Partner Leagues are the American Association, Atlantic League, Frontier League, and Pioneer League. Their recruitment can include open tryouts, as demonstrated by the Frontier League’s 2025 tryout camp and draft. (milb.com)\n\nIn Japan, Nippon Professional Baseball (NPB) has six-club Central and Pacific Leagues; each club played 143 regular-season games in 2025. Its Climax Series selects each league’s representative for the Japan Series, separately from the regular-season league championship. Under regulations announced on August 24, 2026, second- and third-place clubs play a first stage requiring two wins, hosted entirely by the second-place club. The winner faces the league champion, which normally begins the final stage with one credited victory and needs four victories including that advantage. From 2026, the champion instead receives two credited victories, with five required, if its opponent finished at least ten games behind or below a .500 winning percentage. NPB’s 2025 draft regulations also illustrate a distinct recruitment mechanism: clubs must acquire negotiating rights to eligible newcomers, including school, university, and corporate-team players. (npb.or.jp)\n\nThe KBO League in South Korea uses a single ten-club table and a 144-game schedule per club. Its 2025 postseason followed a stepladder: fourth and fifth contested the wild-card round, the survivor faced third, that winner faced second, and the remaining challenger met first in the Korean Series. Fourth place needed only one win or draw in the two-game wild-card round; fifth needed two wins. The subsequent preliminary series were best-of-five and the Korean Series best-of-seven. Roster systems also differ between leagues. MLB’s active roster expands from 26 to 28 players in September. KBO’s 2026 registration included 30 foreign players across its clubs plus ten players under a newly introduced Asian quota, distinguishing that additional category from the established foreign-player allocation. (eng.koreabaseball.com)\n\nThe Chinese Professional Baseball League (CPBL) in Taiwan provides another model. Its six clubs each had 120 games in 2025, divided into two 60-game halves, rather than relying exclusively on one season-long qualification table. When different clubs win the halves, the half-season champion with the better full-season record advances directly to the Taiwan Series; the other meets the highest-ranked remaining club in a preliminary playoff, beginning with one credited victory. The Taiwan Series requires four wins. In 2025, the CTBC Brothers qualified directly, while the Rakuten Monkeys reached the championship series through the preliminary playoff against the Uni-President 7-Eleven Lions. (zh.wikipedia.org)\n\nIn Mexico, the summer Liga Mexicana de Beisbol and winter Liga Mexicana del Pacífico are separate competitions. The summer league’s published 2025 calendar provided 20 clubs with 93 scheduled games each, beginning April 17; six clubs from each of its North and South zones qualified for postseason play, with every series requiring four wins and the final called the Serie del Rey. The Pacific League participates in the Caribbean Series alongside winter-league champions from the Dominican Republic, Puerto Rico, and Venezuela. The January 31–February 7, 2025 edition in Mexicali also admitted the invitational Japan Breeze club, not Japan’s national team or NPB champion. Its five entrants played a round robin followed by semifinals and a final; the Leones del Escogido won the championship game 1–0 against the Charros de Jalisco. (milb.com)"
    },
    {
      "heading": "International Governance and National-Team Events",
      "text": "National federations organize domestic competitions, support affiliated clubs, and administer national teams; continental associations coordinate regional championships and development within the international governing structure. The World Baseball Softball Confederation (WBSC) was formed in 2013 through the merger of the International Baseball Federation and International Softball Federation, whose leaders, Riccardo Fraccari and Don Porter, initially served as co-presidents. Its 2026 Members Handbook recognizes seven continental associations across five geographical regions: Africa, Europe, and Oceania have combined organizations, while the Americas and Asia have separate baseball and softball associations. National-team competitions therefore operate through federations and continental bodies rather than through a single professional-league hierarchy. (s3-eu-west-1.amazonaws.com)\n\nThe World Baseball Classic (WBC) began in March 2006 as an MLB-organized tournament sanctioned by the international federation, providing a national-team competition involving established major-league players. Japan defeated Cuba 10–6 in the inaugural final. For the March 5–17, 2026 edition, 20 teams competed: 16 retained places through their 2023 first-round standings, while Brazil, Chinese Taipei, Colombia, and Nicaragua qualified in 2025. Four five-team pools played round-robin schedules; their top two teams advanced to single-elimination quarterfinals, semifinals, and a final. Qualification thus depended on previous WBC results and separate qualifiers, not simply on WBSC world rankings. (static.wbsc.org)\n\nWBC eligibility extends beyond citizenship to qualifying permanent residence, birthplace, parental connections, or documented entitlement to citizenship. (mlb.com) Its March calendar overlaps MLB spring training rather than the regular season. (apnews.com) Tournament-specific restrictions govern professional pitching workloads: in 2026, pitchers were limited to 65 pitches in the first round, 80 in quarterfinals, and 95 in the championship round, with permission to finish a batter after reaching the limit. Throwing at least 50 pitches required four days’ rest; throwing at least 30 required one day, and pitching on three consecutive days was prohibited. These provisions distinguish participation in the Classic from unrestricted availability for a national team. (img.mlbstatic.com)\n\nThe historical Baseball World Cup ran from 1938 to its final edition in 2011, when the Netherlands defeated Cuba 2–1. It is distinct from both the WBC and Premier12, which began in 2015 with a championship won by South Korea. (en.wikipedia.org) The 2024 Premier12 selected the 12 highest-ranked teams at the end of 2023; unlike the WBC, it excluded players on MLB 40-man rosters. (mlb.com) Its November 9–24 schedule used two six-team opening groups, followed by a four-team round-robin Super Round and medal games. Each roster contained 28 players, including at least 13 pitchers and two catchers. Consequently, ranking-based entry, roster availability, and a second group stage produced a different competition from the Classic’s qualifying and knockout system. (static.wbsc.org)\n\nWBSC age-group World Cups comprise U-12, U-15, U-18, and U-23 competitions. Eligibility is determined by birth year: for example, the June 2024 regulations admitted players born from 2001 through 2006 to that year’s U-23 tournament. Their twelve-team format advanced three teams from each opening group to a six-team Super Round, carrying forward results against other qualifiers. (static.wbsc.org) The Women’s Baseball World Cup, inaugurated in 2004, is a separate national-team championship, not a softball competition. (apnews.com) Its 2023 group stage led to six-team finals in Thunder Bay, Canada, in 2024, illustrating how qualification and championship play can occur in different calendar years. (baseball.ca)\n\nBaseball’s Olympic demonstration tournaments at Los Angeles 1984 and Seoul 1988 did not award official Olympic medals. Medal competition began at Barcelona 1992 and continued through Beijing 2008; baseball was absent in 2012 and 2016. (s3.eu-west-1.amazonaws.com) Tokyo 2020, held in 2021, admitted six teams—Japan, South Korea, Mexico, the United States, Israel, and the Dominican Republic—and used opening pools followed by a knockout bracket with repechage routes, rather than the WBC’s straight single-elimination structure. (s3.eu-west-1.amazonaws.com) Baseball was absent from Paris 2024, while its inclusion at Los Angeles 2028 was approved on October 16, 2023, specifically for that edition, not as a guarantee of participation in every subsequent Games. (en.wikipedia.org)"
    },
    {
      "heading": "Youth, Educational, and Recreational Baseball",
      "text": "Community baseball combines age-group competition with locally organized instruction and volunteer administration. Little League offers tee-ball and coach-pitch divisions before or alongside player-pitch baseball; parents and other volunteers serve as managers, coaches, umpires, and league officers after required screening. Its Major Division accommodates boys and girls aged 9–12, although local leagues may restrict that division to older players within this range. Eligibility involves both league-age classifications and community boundaries: under the provisions applying in 2026, players aged seven and younger may register without geographic restrictions, while older entrants ordinarily qualify through residence, school location, or uninterrupted participation since league age seven. Local participation and selection for tournament teams are separate processes. (littleleague.org)\n\nYouth specifications change with the division rather than following one universal miniature version of adult baseball. Little League Majors uses 60-foot base paths and a 46-foot pitching distance; its Intermediate division, for league ages 11–13, uses 70-foot base paths and a 50-foot pitching distance, before the 90-foot diamond used in Junior and Senior divisions. In the 2026 tournament rules, Major Division games are scheduled for six innings, compared with seven for Intermediate, Junior, and Senior competition. Little League’s bat rules require nonwood and laminated bats in Majors and below to carry USABat certification. Its published pitching regulations set daily limits of 75 pitches for ages 9–10 and 85 for ages 11–12, subject to specified batter-completion exceptions. For pitchers aged 14 and younger, 21–35 pitches require one calendar day’s rest, 36–50 require two, 51–65 require three, and 66 or more require four; these are competition eligibility rules, not individualized medical prescriptions. (littleleague.org)\n\nSchool teams provide another substantial participation structure. In the United States, the National Federation of State High School Associations recorded 471,701 boys participating in baseball during 2023–24. College baseball connects competition with enrollment in higher education, but financial arrangements differ: NCAA Division II uses partial athletic scholarships, while Division III does not award athletic scholarships. In Japan, school tournament competition has its own institutional history: the summer national championship began in 1915, and the spring invitational began in 1924. These educational structures differ from professional-club academies. In the Dominican Republic, Arizona’s academy education program began in 2014, supplementing baseball development with secondary schooling. (nfhs.org)\n\nParticipation also depends on registration charges, equipment, playable facilities, and the people available to organize instruction. Little League’s 2024 impact report identifies equipment provision, field refurbishment, and volunteer training among its funded activities. Its T-Mobile Call Up Grant addresses a narrower expense—registration fees—and the program reported assisting more than 82,000 families since 2020 in its August 2026 update. Such community provision is distinct from recruitment-oriented academy training: registration support finances access to organized play rather than entry into a professional development system. (littleleague.org)\n\nAdult amateur baseball provides organized competition outside school enrollment or professional employment. The Men’s Senior Baseball League/Men’s Adult Baseball League offers local leagues and regional and national tournaments, with age thresholds including 18, 25, 35, 45, and 55. Its structure allows players to continue competing against age-group peers rather than treating amateur participation solely as a preliminary stage of professional recruitment. Clubs organize seasonal schedules and playoffs, while tournament participation provides additional competition beyond the local league. (msblnational.com)\n\nAdaptive programs alter participation arrangements for players with disabilities. Little League’s Challenger Division generally accommodates ages 4–18, extending to 22 for participants still enrolled in school; Senior Challenger begins at 15 without a maximum age. Games typically last one or two innings, every player bats each inning, and “buddies” assist with batting, baserunning, or defense only as needed. Batting tees and coach pitching can replace player pitching. Miracle League programs make a different environmental adaptation: custom rubberized fields accommodate wheelchairs and other mobility devices, alongside a buddy system. Its first field opened in Conyers, Georgia, in April 2000. (littleleague.org)"
    },
    {
      "heading": "Women’s Baseball and Related Bat-and-Ball Games",
      "text": "Organized women’s baseball in the United States dates to the nineteenth century: Vassar College formed a women’s team in 1866, while commercial women’s touring teams appeared in the 1870s. From approximately the 1890s, “Bloomer Girls” clubs travelled between towns, selling tickets to games against local opposition rather than belonging to a permanent league. These clubs were not necessarily exclusively female. Margaret Nabel’s New York Bloomer Girls, active into the 1930s, played men’s teams, Black clubs, and other women’s teams. Such touring enterprises provided paid playing opportunities distinct from college and community baseball. (baseballhall.org)\n\nPhilip K. Wrigley helped establish the All-American Girls Professional Baseball League (AAGPBL) in 1943, during World War II. Its inaugural four clubs—the Rockford Peaches, South Bend Blue Sox, Racine Belles, and Kenosha Comets—played a 108-game regular-season schedule. More than 600 women participated during its twelve seasons, ending in 1954. The playing specifications changed substantially: initially, pitchers delivered underhand from 40 feet, bases were 65 feet apart, and the ball measured 12 inches in circumference. Baseball-style rules nevertheless permitted runners to lead off bases. Overhand pitching became mandatory in 1948, when the pitching distance was 50 feet, base paths 72 feet, and ball circumference \\(10\\frac{3}{8}\\) inches. By 1954, the league used a nine-inch ball, 85-foot base paths, and a 60-foot pitching distance—close to, but not identical with, the conventional adult baseball diamond. (aagpbl.org)\n\nBlack women’s professional participation followed a different route because the AAGPBL did not admit them. Toni Stone played second base for the Indianapolis Clowns in 1953 and the Kansas City Monarchs in 1954; pitcher Mamie “Peanut” Johnson and second baseman Connie Morgan also played for the Clowns during the 1950s. Their careers demonstrate participation in otherwise male professional clubs, not the existence of a broadly accessible women’s league. Later opportunities likewise took several forms: the Colorado Silver Bullets toured against men’s opposition from 1994 through 1997, while Ila Borders signed with the independent St. Paul Saints in 1997. At the amateur level, Olivia Pichardo appeared for Brown University in 2023, becoming the first woman to play in an NCAA Division I baseball game. (baseballhall.org)\n\nContemporary pathways include girls’ clubs, dedicated tournaments, and federation-selected national teams. Baseball For All’s national tournament connects girls’ teams from different communities; USA Baseball selected a twenty-player women’s national roster on June 15, 2026, following its training camp. International women’s baseball uses baseball equipment and pitching, rather than softball rules. Women also work throughout baseball’s non-playing institutions: Alyssa Nakken joined the San Francisco Giants’ major-league coaching staff in 2020, Kim Ng became the Miami Marlins’ general manager that year, and baseball journalist Claire Smith received the BBWAA Career Excellence Award in 2017. On August 9, 2025, Jen Pawol became the first woman to umpire a regular-season Major League Baseball game. (baseballforall.com)\n\nSoftball is a separate sport played by both women and men, not simply a name for women’s baseball. Under the WBSC’s 2022–2025 fast-pitch rules, adult play used a larger, approximately 12-inch-circumference ball, 60-foot base paths, and underhand pitching from 43 feet for women or 46 feet for men. Its scoring still requires completing the circuit of bases. Rounders instead uses a short bat, underarm bowling, and four posts: under Rounders England’s published simplified rules, a batter ordinarily scores one rounder by hitting the ball and reaching the fourth post before the next delivery; specified situations earn half-rounders. (static.wbsc.org)\n\nCricket replaces the diamond with two wickets at opposite ends of a 22-yard pitch and uses a broad, flat-faced bat. Bowlers deliver with the arm action regulated by cricket’s laws, and the ball may bounce before reaching the striker. Two batters score runs by exchanging ends, while boundary hits and penalties can add runs without running. Baseball5 retains a base circuit but removes the bat, pitcher, and fielding gloves: five players per side use a rubber ball that the hitter strikes with a bare palm or fist. Its bases are 13 metres apart, and teams alternate after three outs in a standard five-inning game. (lords.org)"
    },
    {
      "heading": "Scorekeeping, Statistics, and Analytical Research",
      "text": "A scorecard preserves the sequence of plate appearances, outs, and runners’ advances; a box score condenses the game into individual and team totals. Conventional notation includes “K” for a strikeout and “6–3” for a shortstop-to-first-baseman putout. (mlb.com) Official scorers determine statistical classifications rather than umpiring decisions. Under the 2026 Official Baseball Rules, a misplay is judged against what a fielder could accomplish with ordinary effort: touching a ball does not automatically make a subsequent failure an error. Reaching on a fielder’s choice is distinct from recording a hit. Scorers also distinguish wild pitches from passed balls and determine earned runs by reconstructing an inning without errors, subject to specified exceptions, and passed balls. Consequently, an earned run is a rule-defined accounting category, not a complete measure of a pitcher’s responsibility. (mktg.mlbstatic.com)\n\nStandard batting rates use different denominators. With \\(H\\) denoting hits, \\(AB\\) at-bats, \\(BB\\) walks, \\(HBP\\) hit-by-pitches, and \\(SF\\) sacrifice flies, batting average is \\(AVG=H/AB\\), while on-base percentage is \\(OBP=(H+BB+HBP)/(AB+BB+HBP+SF)\\). Walks, hit-by-pitches, and sacrifices are not at-bats; reaching on an error does not enter the OBP numerator. (mktg.mlbstatic.com) Slugging percentage weights singles, doubles, triples, and home runs by bases gained:\n\n\\[SLG=\\frac{1B+2(2B)+3(3B)+4HR}{AB},\\qquad OPS=OBP+SLG.\\]\n\nThese weights count total bases rather than exact contributions to scoring. (library.fangraphs.com) For example, a hypothetical batter with 30 hits in 100 at-bats—20 singles, six doubles, one triple, and three home runs—has a .300 average and .470 slugging percentage. Adding ten walks, two hit-by-pitches, and three sacrifice flies gives \\(OBP=42/115=.365\\) and \\(OPS=.835\\), rounded to three decimal places.\n\nPitching rates include earned run average, \\(ERA=9ER/IP\\), where \\(ER\\) is earned runs and \\(IP\\) innings pitched, and walks plus hits per inning pitched, \\(WHIP=(BB+H)/IP\\). (mktg.mlbstatic.com) A hypothetical pitcher allowing 20 earned runs, 50 hits, and 15 walks in 60 innings has a 3.00 ERA and 1.083 WHIP. Innings are measured in thirds: a displayed “6.1” means six innings and one out, or \\(6\\frac13\\), not 6.1 decimal innings. (mktg.mlbstatic.com)\n\nHenry Chadwick’s 1859 box score recorded runs, hits, putouts, assists, and errors, helping establish comparable numerical records. (baseballhall.org) Sabermetrics extends that descriptive tradition into research on scoring, strategy, and player value. Bill James began self-publishing the Baseball Abstract in 1977 and coined “sabermetrics” in the 1980 edition, drawing the name from the Society for American Baseball Research. His early Abstracts examined runs created, park effects, replacement value, and other analytical concepts. (sabr.org) The distinction is methodological: a recorded hit describes an officially classified event, whereas an estimate of the wins contributed by that hit depends on a model and its assumptions. (baseball-reference.com)\n\nRun expectancy is the expected number of runs remaining in an inning for each of 24 states: eight possible arrangements of occupied bases multiplied by zero, one, or two outs. A play’s run-expectancy value equals runs scored plus expectancy afterward minus expectancy beforehand. (library.fangraphs.com) Win expectancy additionally incorporates score and inning; win probability added measures its change across a play, making it sensitive to game circumstances rather than simply underlying skill. (library.fangraphs.com) Park and league adjustments place production within its scoring environment: OPS+, for example, uses 100 as league average. (library.fangraphs.com) Wins above replacement (WAR) instead compares estimated contributions with a theoretical readily available replacement, not an average player or the actual bench substitute. (baseball-reference.com) Position-player models combine batting, baserunning, fielding, positional, and replacement adjustments. Pitcher implementations differ particularly sharply: FanGraphs principally uses fielding-independent pitching, while Baseball-Reference begins with runs allowed and adjusts for defensive support. (library.fangraphs.com)\n\nObserved rates do not establish talent with equal precision. Sample size requirements differ by statistic, and a short hot streak can substantially alter batting average without demonstrating a lasting change in ability. (library.fangraphs.com) Historical coverage introduces additional uncertainty: Retrosheet identifies missing games in many pre-1969 seasons and distinguishes reconstructed event accounts from surviving play-by-play descriptions. Matching a box score’s totals does not necessarily recover the correct sequence of events. (retrosheet.org) Park and era adjustments improve comparisons, but express performance relative to the chosen league environment; they do not turn different periods or competition levels into identical conditions. (library.fangraphs.com)"
    },
    {
      "heading": "Tracking Technology and Performance Measurement",
      "text": "Radar and optical tracking record different aspects of baseball motion. Doppler radar detects frequency changes in reflected microwaves to measure a moving ball; successive observations support estimates of its flight characteristics. Optical systems use synchronized cameras and computer vision to reconstruct ball and player positions in three dimensions. MLB installed Statcast in all 30 ballparks in 2015. Its original configuration combined TrackMan radar for ball tracking with cameras for player tracking; in 2020, MLB adopted Hawk-Eye’s optical platform. Twelve synchronized cameras also enabled reconstruction of players’ three-dimensional skeletal models, extending measurement from where a player moved to how the body moved. (login.trackman.com)\n\nHigh-speed video resolves movements that ordinary broadcast footage cannot adequately separate, including changes immediately around release and bat–ball contact. Markerless motion capture estimates body landmarks from multiple views rather than requiring players to wear reflective markers. MLB’s technology presentation in 2026 described 300-frame-per-second biomechanical data; Hawk-Eye’s baseball systems also measure bat speed, swing path, and attack angle. These outputs require distinct interpretations: bat speed describes the bat’s motion, attack angle describes its direction at impact, and exit velocity describes the departing ball. A skeletal reconstruction is likewise an estimated model derived from images, not a direct measurement of muscle activity or joint loading. (usenix.org)\n\nPitch velocity is normally reported in miles per hour at release, rather than at home plate, where the ball has slowed. Baseball Savant’s documentation distinguishes 2008–2016 PITCHf/x velocities, adjusted to approximate release speed, from Statcast’s out-of-hand measurements beginning in 2017. Pitch movement requires an equally explicit reference: total vertical movement includes gravity, whereas induced vertical movement removes its contribution. Savant compares total movement with pitches of the same type within 2 mph of velocity and 0.5 feet of extension and release position, limiting the misleading advantage slower pitches acquire simply through longer flight time. For hitting, exit velocity measures ball speed after contact and launch angle its initial vertical direction; Statcast classifies contact at 95 mph or more as “hard hit,” irrespective of whether it becomes a hit or an out. (baseballsavant.mlb.com)\n\nRunning and fielding measurements distinguish physical performance from recorded results. Sprint Speed uses distance covered during a runner’s fastest one-second window; a seasonal figure averages approximately the fastest two-thirds of qualifying runs, rather than every movement on the bases. A run reaching 30 feet per second receives the label “Bolt.” Outfield Catch Probability translates tracking observations into a probability using opportunity time, the shortest distance needed, and direction of travel. It is therefore a model of fielding difficulty, not another sensor reading. For example, catching a ball assigned a 25% probability contributes \\(1-0.25=0.75\\) to outfield Outs Above Average; failing to catch it contributes \\(-0.25\\). This evaluates performance relative to opportunities rather than treating all catches as equally difficult. (baseballsavant.mlb.com)\n\nTracking supports scouting and development by describing pitch release, movement, contact quality, and player motion independently of a short sequence of game outcomes. Portable practice systems extend ball measurement to training settings, while biomechanical platforms allow analysis of pitchers’ and hitters’ movements. For opponent preparation, Baseball Savant provides pitcher-arsenal reports, positional visualizations, and filters for individual pitches, players, teams, and seasons. Broadcast applications turn the same positional information into reconstructed plays: MLB’s 2020 technology announcement described virtual viewpoints from a defender’s position or even the baseball’s perspective. These presentations illustrate measured trajectories without making their visual drama a measure of player value. (trackman.com)\n\nCalibration, coordinate conventions, and missing observations constrain comparisons. Camera-based reconstruction depends on placing synchronized views within a common spatial reference; published tables additionally depend on field definitions and processing choices. Savant includes estimated exit velocities and launch angles for some balls not tracked directly. Its documentation also records a concrete discontinuity: through 2025, pitch-location coordinates referred to the front of home plate; beginning in 2026, they refer to its middle. Public pitch-level downloads should not be equated with complete proprietary camera streams or biomechanical datasets. Reproducibility consequently depends on identifying the downloaded data version, coordinate definitions, estimated observations, selection filters, and analytical code, not merely naming Statcast as the source. (sony.com)"
    },
    {
      "heading": "Business, Labor Relations, and Competitive Integrity",
      "text": "Professional clubs combine sporting operations with commercial businesses. Ownership may take corporate form: Atlanta Braves Holdings, a publicly traded company, indirectly owns the Braves and the adjacent Battery Atlanta development. Its 2024 accounts reported $663 million in total revenue, including $595.4 million from baseball operations. Club income includes tickets, concessions, premium seating, local broadcasting, sponsorship, merchandise, and licensing; centrally negotiated MLB broadcasting and licensing agreements provide additional shared income. These categories respond differently to sporting results: postseason qualification creates additional ticket-selling opportunities, whereas multiyear broadcasting and sponsorship contracts provide contractual revenue streams. Licensing also monetizes club names and logos as intellectual property, separately from admission to games. (sec.gov)\n\nPlayer employment historically operated through the reserve system, under which clubs claimed continuing rights to players beyond individual contract terms, restricting their access to the labor market. The Major League Baseball Players Association (MLBPA), led by executive director Marvin Miller from 1966, developed collective bargaining and neutral grievance arbitration as mechanisms for challenging those restrictions. On December 23, 1975, arbitrator Peter Seitz ruled for pitchers Andy Messersmith and Dave McNally, rejecting perpetual reservation through repeated contract renewal. Under the 2022–2026 agreement, eligible players generally enter salary arbitration after three years of major-league service, with an earlier “Super Two” category, and may become free agents after six years when no continuing contract binds them. Arbitration panels select either the player’s or club’s proposed salary rather than a compromise figure; negotiated extensions can replace that annual process. (mlbplayers.com)\n\nLabor stoppages distinguish player-initiated strikes from employer-initiated lockouts. The 1972 strike concerned pension funding and ended with an additional $500,000 owner contribution. The strike beginning August 12, 1994, interrupted bargaining over the sport’s economic system and ultimately eliminated the remainder of the season, including the World Series. These disputes affected not only compensation but also the allocation of bargaining power between collectively organized players and clubs. (mlbplayers.com) The owners’ 99-day lockout ended on March 10, 2022, with agreement on terms covering the 2022–2026 seasons. (mlb.com)\n\nStadium finance and payroll regulation redistribute costs and resources through different mechanisms. For Truist Park, which opened in Georgia in 2017, the projected $672 million construction cost comprised $372 million from the Braves and $300 million from Cobb County; subsequent overruns increased the club’s contribution while leaving the county’s construction contribution unchanged. Public financing therefore concerns capital expenditure, not simply player salaries. (s3.amazonaws.com) MLB’s 2022–2026 agreement defines revenue-sharing transfers using a benchmark equivalent to a 48% pool of net local revenues. Its competitive-balance tax is not a hard salary cap: clubs may exceed the threshold but incur financial penalties. The threshold reaches $244 million in 2026, with base rates of 20%, 30%, and 50% for successive years above it, plus applicable surcharges. Tax payroll incorporates contract average annual values and benefit costs rather than merely that season’s cash payments. (mlbplayers.com)\n\nThe Black Sox scandal concerned the fixing of the 1919 World Series between the Chicago White Sox and Cincinnati Reds. It helped precipitate the appointment of federal judge Kenesaw Mountain Landis as baseball’s first commissioner, with broad disciplinary authority. In 1921, Landis excluded eight White Sox players despite their acquittal in criminal court, demonstrating the distinction between criminal verdicts and eligibility decisions within organized baseball. The exclusions should not be treated as proof that each player performed the same role in the conspiracy. (baseballhall.org) Published Major League Rule 21 separately specifies a one-year ineligibility penalty for betting on baseball games in which the bettor has no duty, and permanent ineligibility for betting on games connected with the bettor’s duties. (content.mlb.com)\n\nAnti-doping enforcement operates through the jointly negotiated MLB–MLBPA Drug Prevention and Treatment Program, which specifies testing, prohibited substances, disciplinary procedures, and appeal mechanisms. Its standard progression for positive tests involving performance-enhancing substances is an unpaid 80-game suspension, then 162 games, then permanent suspension, subject to the program’s reinstatement provisions. Different substance categories and other violations have distinct procedures and penalties; those sanctions are not interchangeable. (mlb.mlb.com) Equipment enforcement addresses another form of competitive integrity: MLB’s June 2021 guidance introduced routine pitcher inspections, with ejection and ten-game suspension for prohibited foreign substances. (mlb.com)"
    },
    {
      "heading": "Cultural Expression, Spectatorship, and Historical Memory",
      "text": "In the United States, baseball’s designation as the “national pastime” expresses a cultural identity rather than a claim of universal participation or allegiance. Nineteenth-century clubs, newspapers, and promoters helped associate the game with American civic life, although its geographical reach was initially uneven. Other societies developed distinct attachments to the sport rather than simply adopting this American symbolism. In Japan, organized cheering makes club allegiance a collective performance; in the Caribbean, baseball traditions also travel through migration. The Smithsonian’s ¡Pleibol! exhibition documents how migrants from Cuba, the Dominican Republic, and Puerto Rico brought established baseball experiences into American communities during the twentieth century. These connections make baseball a medium of local belonging and transnational identification, not an exclusively American cultural possession. (loc.gov)\n\nSpectators participate through practices that extend beyond watching play. Keeping a personal scorecard produces a handwritten record of plate appearances, outs, and runners’ progress, distinct from the official scorer’s record. In American ballparks, communal singing during the seventh-inning stretch links spectatorship to music and food imagery. “Take Me Out to the Ball Game,” written in 1908 by lyricist Jack Norworth and composer Albert Von Tilzer, names peanuts and Cracker Jack in its familiar chorus. Its less frequently performed verses concern Katie Casey, a knowledgeable woman who prefers attending baseball to another entertainment outing. The chorus’s ballpark use therefore preserves only part of the original song’s narrative. (en.wikipedia.org)\n\nJapanese supporter groups, or ōendan, organize a different form of participation: drums, brass instruments, flags, and coordinated chants turn sections of the stands into ensembles. Cheers can change according to the opposing team and the batter, requiring shared repertoires and leaders who coordinate performance. The Japan National Tourism Organization describes supporters wearing festival-style clothing bearing club insignia and using taiko drums. Such practices illustrate how spectators can produce the soundscape of a game themselves, rather than responding only to announcements or recorded entertainment. They are characteristic practices within Japanese baseball culture, not a description of every Japanese spectator. (faq.japan-travel.jnto.go.jp)\n\nJournalism and broadcasting have made baseball accessible beyond the stadium. On August 5, 1921, Harold Arlin described a Phillies–Pirates game from Pittsburgh’s Forbes Field over KDKA, an early landmark in major-league radio broadcasting. Preserved recordings retain announcers’ voices, pacing, and descriptions alongside the sporting events: the Library of Congress’s John Miley Collection includes all seven games of the 1955 World Series among more than 6,000 historical sports broadcasts. Newspapers also provided a setting for baseball literature. Ernest L. Thayer’s “Casey at the Bat” first appeared in San Francisco’s Daily Examiner on June 3, 1888; its fictional hometown hero’s strikeout became a durable representation of disappointed collective expectation. (apnews.com)\n\nBaseball’s visual and dramatic representations include Norman Rockwell’s Three Umpires, which depicts officials considering threatening weather, and Penny Marshall’s film A League of Their Own (1992). The latter uses the All-American Girls Professional Baseball League of 1943–1954 as the setting for a fictional story; its characters and incidents should not be treated as a documentary account. Its selection for the National Film Registry in 2012 recognizes the film’s cultural significance separately from the historical league’s achievements. Baseball also supplies everyday metaphors: “throw a curveball,” for example, transfers the pitch’s disruption of a batter’s expectations to an unexpected complication outside sport. (sabr.org)\n\nMuseums, archives, and preserved ballparks maintain different kinds of historical evidence. Cooperstown’s National Baseball Hall of Fame and Museum, opened on June 12, 1939, preserves equipment and uniforms; its archives also catalogue recorded interviews, while the Library of Congress holds newspapers, photographs, cards, and broadcast material. Historic grounds preserve spatial experience: Wrigley Field received National Historic Landmark designation on November 19, 2020, following restoration work begun in 2014. Commemorative status, however, does not establish every associated story. Cooperstown’s 1939 “centennial” reflected the claim that Abner Doubleday invented baseball there in 1839; the Hall itself identifies that claim as a refuted myth and notes that Doubleday was then at West Point. (baseballhall.org)"
    }
  ],
  "links": [
    "united-states",
    "caribbean",
    "boston",
    "weather",
    "gravity",
    "momentum",
    "expected-value",
    "probability",
    "new-york-city",
    "camera",
    "north-america",
    "world-war-ii",
    "los-angeles",
    "san-francisco",
    "montreal",
    "toronto",
    "statistics",
    "cuba",
    "puerto-rico",
    "education",
    "dominican-republic",
    "japan",
    "south-korea",
    "taiwan",
    "venezuela",
    "mexico",
    "canada",
    "australia",
    "europe",
    "netherlands",
    "olympic-games",
    "higher-education",
    "disability",
    "radar",
    "computer-vision",
    "calibration",
    "reproducibility",
    "intellectual-property",
    "labor-market",
    "music",
    "journalism",
    "literature",
    "film",
    "metaphor",
    "museum"
  ],
  "sources": [
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      "url": "https://mktg.mlbstatic.com/mlb/official-information/2026-official-baseball-rules.pdf"
    },
    {
      "title": "Field Specifications - Little League",
      "url": "https://www.littleleague.org/league-officials/field-specifications/"
    },
    {
      "title": "2019 Official Baseball Rules",
      "url": "https://img.mlbstatic.com/mlb-images/image/upload/mlb/ub08blsefk8wkkd2oemz.pdf"
    },
    {
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      "url": "https://www.littleleague.org/playing-rules/bat-rules/"
    },
    {
      "title": "Appendix B - Safety Code for Little League",
      "url": "https://www.littleleague.org/playing-rules/appendices/appendix-b/"
    },
    {
      "title": "2022 Boston Red Sox Media Guide",
      "url": "https://img.mlbstatic.com/mlb-images/image/upload/fl_attachment/mlb/kdnzrsvryd8tcxzq6tbt.pdf"
    },
    {
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    },
    {
      "title": "Chase Field: Home of the D-backs | Arizona Diamondbacks",
      "url": "https://www.mlb.com/dbacks/ballpark"
    },
    {
      "title": "Tropicana Field 2024 Ground Rules",
      "url": "https://img.mlbstatic.com/mlb-images/image/upload/mlb/sak6bue9pzuie7eqka7g.pdf"
    },
    {
      "title": "Hit (H) | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/standard-stats/hit"
    },
    {
      "title": "Run (R) | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/standard-stats/run?msockid=3a3901ca0dca6e2c0c19170e0c626fa5"
    },
    {
      "title": "Walk-off (WO) | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/standard-stats/walk-off"
    },
    {
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      "url": "https://www.mlb.com/glossary/rules/designated-runner"
    },
    {
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    },
    {
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    },
    {
      "title": "The 8, 10, and 15-Run Rules: What Parents Need to Know",
      "url": "https://www.littleleague.org/university/articles/the-10-run-rule-what-parents-need-to-know/"
    },
    {
      "title": "Official Baseball Rules: Definitions of Terms",
      "url": "https://img.mlbstatic.com/mlb-images/image/upload/mlb/hhvryxqioipb87os1puw.pdf"
    },
    {
      "title": "2019 Official Baseball Rules",
      "url": "https://content.mlb.com/documents/2/2/4/305750224/2019_Official_Baseball_Rules_FINAL_.pdf"
    },
    {
      "title": "What's the Score?: The Basics of Scorekeeping",
      "url": "https://www.littleleague.org/university/articles/scorekeeping-101/"
    },
    {
      "title": "Baseball positions",
      "url": "https://en.wikipedia.org/wiki/Baseball_positions"
    },
    {
      "title": "Designated Hitter | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/designated-hitter"
    },
    {
      "title": "Relief Pitcher | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/relief-pitcher"
    },
    {
      "title": "Closer | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/closer"
    },
    {
      "title": "Zobrist is 'Father of Utility' in Rays' organization",
      "url": "https://www.mlb.com/news/ben-zobrist-is-father-of-utility-in-rays-organization/c-69110028"
    },
    {
      "title": "Two-way player rule impact on MLB",
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    },
    {
      "title": "Manager | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/manager?msockid=04216c70a23660490c137ae5a36061f6"
    },
    {
      "title": "Bench Coach | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/bench-coach"
    },
    {
      "title": "First-base Coach | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/first-base-coach"
    },
    {
      "title": "Third-base Coach | Glossary | MLB.com",
      "url": "https://www.mlb.com/glossary/positions/third-base-coach"
    },
    {
      "title": "Pitching Mechanics: What's in a Release Point?",
      "url": "https://ericcressey.com/pitching-mechanics-release-point/"
    },
    {
      "title": "Magrane on the difference between command and control",
      "url": "https://www.mlb.com/video/magrane-on-command-vs-control-c1379702283"
    },
    {
      "title": "Four-Seam Fastball (FA)",
      "url": "https://www.mlb.com/glossary/pitch-types/four-seam-fastball"
    },
    {
      "title": "Cutter (FC)",
      "url": "https://www.mlb.com/glossary/pitch-types/cutter"
    },
    {
      "title": "Slider (SL)",
      "url": "https://www.mlb.com/glossary/pitch-types/slider"
    },
    {
      "title": "Changeup (CH)",
      "url": "https://www.mlb.com/glossary/pitch-types/changeup?msockid=0888aee4189b64030c06b87d1934652d"
    },
    {
      "title": "Identifying pitch types: A fan's guide",
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    },
    {
      "title": "Hitting Coach: Facilitator Guide",
      "url": "https://nccp.baseball.ca/pdfs/fac/en/Instructor%20Beginner%20-%20Hitting%20-%20Facilitator%20Guide%20-%20English.pdf"
    },
    {
      "title": "Shelburne Little League Baseball Coaching Manual – Skills and Drills",
      "url": "https://www.champlainvalleylittleleague.org/portals/29666/docs/coaches%20corner/skills%20and%20drills.pdf"
    },
    {
      "title": "Bunting 101: The Bunting Progression",
      "url": "https://www.littleleague.org/university/articles/bunting-101-the-bunting-progression/"
    },
    {
      "title": "Catcher",
      "url": "https://www.mlb.com/glossary/positions/catcher?msockid=3bff4f3d24c165c820c159402530647f"
    },
    {
      "title": "3 Things All Catchers Must Know",
      "url": "https://www.littleleague.org/university/articles/3-things-all-catchers-must-know/"
    },
    {
      "title": "Pitch Sequence Complexity and Long-Term Pitcher Performance",
      "url": "https://mdpi-res.com/d_attachment/sports/sports-03-00040/article_deploy/sports-03-00040.pdf"
    },
    {
      "title": "Tactics and Strategies",
      "url": "https://cdn1.sportngin.com/attachments/document/6a43-2281638/chp9.pdf"
    },
    {
      "title": "Baseball Coaches and Team Managers Manual",
      "url": "https://michiganlegion.org/assets/baseball/Baseball_Coaches_Manual.pdf"
    },
    {
      "title": "Squeeze play (baseball)",
      "url": "https://en.wikipedia.org/wiki/Squeeze_play_%28baseball%29"
    },
    {
      "title": "The Run Expectancy Matrix, Reloaded for the 2020s",
      "url": "https://blogs.fangraphs.com/the-run-expectancy-matrix-reloaded-for-the-2020s/"
    },
    {
      "title": "Tradition not always order of day in building lineups",
      "url": "https://www.mlb.com/news/tradition-not-always-order-of-day-in-building-lineups/c-41999022"
    },
    {
      "title": "Third Time Through the Order Penalty",
      "url": "https://www.mlb.com/glossary/miscellaneous/third-time-through-the-order-penalty"
    },
    {
      "title": "Three-batter Minimum",
      "url": "https://www.mlb.com/glossary/rules/three-batter-minimum?msockid=33d87a124aa06b1d2c096c9e4b276a39"
    },
    {
      "title": "Baseball Rules Interpretations - 2025",
      "url": "https://www.nfhs.org/resources/sports/baseball-rules-interpretations-2025"
    },
    {
      "title": "NCAA Baseball Playing Rules",
      "url": "https://www.ncaa.org/championships/playing-rules/baseball-playing-rules/"
    },
    {
      "title": "Regular Season Rules and Regulations Spotlight: Player Re-Entry, Special Pinch-Runner, Pitch Count, and Mandatory Play",
      "url": "https://www.littleleague.org/university/articles/rules-and-regulations-spotlight-player-re-entry-special-pinch-runner-pitch-count-and-mandatory-play/"
    },
    {
      "title": "WBSC Baseball World Cups – Tournament Regulations, revised 29 May 2025",
      "url": "https://static.wbsc.org/uploads/federations/282/documents/b44b4f13-317b-7f73-2371-52312b863d75.pdf"
    },
    {
      "title": "Why is a game 9 innings? These are the backstories behind baseball's iconic rules",
      "url": "https://www.mlb.com/cut4/stories-behind-baseball-rules-c210241338"
    },
    {
      "title": "Why is the baseball mound 60 feet, 6 inches away?",
      "url": "https://www.mlb.com/news/why-is-the-mound-60-ft-6-inches-away"
    },
    {
      "title": "Why doesn't the National League have the DH?",
      "url": "https://www.mlb.com/news/why-doesn-t-the-national-league-have-the-dh"
    },
    {
      "title": "MLB 2022 season FAQ",
      "url": "https://www.mlb.com/news/mlb-2022-season-faq"
    },
    {
      "title": "MLB rule changes for 2022",
      "url": "https://www.mlb.com/news/mlb-rule-changes-for-2022"
    },
    {
      "title": "MLB rule changes for 2020 season",
      "url": "https://www.mlb.com/news/mlb-rule-changes-for-2020-season"
    },
    {
      "title": "Replay Review",
      "url": "https://www.mlb.com/glossary/rules/replay-review?msockid=35e337ecef3f6de10d6e2187eeda6c05"
    },
    {
      "title": "Champions of America: Early Baseball Card",
      "url": "https://blogs.loc.gov/loc/2017/04/champions-of-america-early-baseball-card/"
    },
    {
      "title": "If You Print It, They Will Come: Baseball’s Early Years",
      "url": "https://blogs.loc.gov/bibliomania/2025/05/28/if-you-print-it-they-will-come-baseballs-early-years/?loclr=blogfam"
    },
    {
      "title": "May 31, 1858: Winthrop tops Olympic in first match game played under ‘Massachusetts’ rules",
      "url": "https://sabr.org/gamesproj/game/may-31-1858-winthrop-tops-olympic-in-first-match-game-played-under-massachusetts-rules/"
    },
    {
      "title": "September 9, 1858: The New York rules in New England",
      "url": "https://sabr.org/gamesproj/game/september-9-1858-the-new-york-rules-in-new-england/"
    },
    {
      "title": "The Ongoing Fable of Baseball",
      "url": "https://www.nysarchivestrust.org/application/files/7515/6831/4781/archivesmag_spring2003.pdf"
    },
    {
      "title": "1857 Winter Meetings: The First Baseball Convention",
      "url": "https://sabr.org/journal/article/1857-winter-meetings-the-first-baseball-convention/"
    },
    {
      "title": "Baseball Americana: The ‘Unchanging’ Game",
      "url": "https://blogs.loc.gov/loc/2018/06/baseball-americana-the-unchanging-game/"
    },
    {
      "title": "1858 Winter Meetings: Building on the Foundation",
      "url": "https://sabr.org/journal/article/1858-winter-meetings-building-on-the-foundation/"
    },
    {
      "title": "History of Doubleday Field",
      "url": "https://baseballhall.org/about-the-hall/history/history-of-doubleday-field"
    },
    {
      "title": "History of the Museum",
      "url": "https://baseballhall.org/about-the-hall"
    },
    {
      "title": "Pro baseball began in Cincinnati in 1869",
      "url": "https://baseballhall.org/discover/pro-baseball-began-in-cincinnati-in-1869"
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      "url": "https://baseballhall.org/research/finding-aid/ba-mss-55"
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      "title": "Did Bud Fowler Almost Break the Major-League Color Line In 1888?",
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    {
      "title": "Miñoso, Minnie",
      "url": "https://baseballhall.org/hall-of-famers/minoso-minnie"
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      "title": "Esteban Bellán charted the way for Latino ballplayers",
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    {
      "title": "The Dominican Republic and the United States: A Baseball History",
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      "url": "https://onlinemuseum.koreabaseball.com/KoreaBaseballHistory/KoreaBaseballHistory.aspx"
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      "title": "Clemente’s lone minor league season put him on a path to Pittsburgh",
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      "title": "Museo de Beisbol de Venezuela y Salon de la Fama",
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      "title": "#Shortstops: Taking the Series worldwide",
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      "title": "MLB New Minor League Structure",
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      "title": "Space Cowboys Become Members of Pacific Coast League",
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      "title": "2026年 セ・パ クライマックスシリーズについてのお知らせ",
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      "title": "World Baseball Softball Confederation: Inaugural Congress address",
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      "title": "2026 WBC Game Notes March 16",
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      "title": "World Baseball Classic rules and rule modifications 2026",
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      "title": "Little League Baseball® Divisions",
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      "title": "FAQs: Residency and School Attendance Eligibility",
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      "url": "https://www.littleleague.org/playing-rules/pitch-count/"
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      "title": "Participation in High School Sports Tops Eight Million for First Time in 2023-24",
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      "title": "Scholarships & Financial Aid",
      "url": "https://www.ncaa.org/student-athletes/scholarships-and-financial-aid/"
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    {
      "title": "大会小史 | 選手権大会",
      "url": "https://jhbf.or.jp/sensyuken/history/"
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    {
      "title": "大会小史 | 選抜大会",
      "url": "https://www.jhbf.or.jp/senbatsu/history/"
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      "title": "Diamondbacks celebrate 12th class of Dominican education program graduates",
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      "title": "T-Mobile Little League® Call Up Grant Program",
      "url": "https://www.littleleague.org/Call-Up-Grant-Program/"
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      "title": "The History of Women in Baseball",
      "url": "https://baseballhall.org/women-in-baseball"
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      "title": "At Home on the Road",
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      "title": "Artifact collection of former Bloomer Girls star preserved at the Hall of Fame",
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      "title": "Baseball For All National Girls Baseball Tournament",
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    {
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    {
      "title": "Walks And Hits Per Inning Pitched (WHIP) | Glossary | MLB.com",
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      "title": "Wins Above Replacement (WAR) | Baseball-Reference.com",
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    {
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      "title": "Sample Size | Sabermetrics Library",
      "url": "https://library.fangraphs.com/principles/sample-size/"
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      "title": "Log In to TrackMan: Terms and Conditions",
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    {
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    {
      "title": "Making Sports More Exciting Through Visualization Technology",
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      "title": "SEC Chooses Hawk-Eye Innovations, Implements ABS Challenge System for 2026 Baseball Tournament",
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      "url": "https://www.trackman.com/baseball"
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    {
      "title": "ATLANTA BRAVES HOLDINGS, INC.—December 31, 2024",
      "url": "https://www.sec.gov/Archives/edgar/data/1958140/000155837025002009/batra-20241231x10k.htm"
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      "title": "Timeline: The Players’ Movement in Baseball",
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    {
      "title": "The Senate and the 1994–95 Baseball Strike",
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    {
      "title": "MLB, MLBPA agree to CBA",
      "url": "https://www.mlb.com/news/mlb-mlbpa-agree-to-cba"
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    {
      "title": "Guide to the Black Sox Scandal (American League)",
      "url": "https://baseballhall.org/discover-more/digital-collection/ba-mss-16"
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    {
      "title": "Landis, Kenesaw",
      "url": "https://baseballhall.org/hall-of-famers/landis-kenesaw"
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    {
      "title": "Major League Rule 21",
      "url": "https://content.mlb.com/documents/8/2/2/296982822/Major_League_Rule_21.pdf?os=fno_journeystrueno_journeys%3Dtrue"
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    {
      "title": "Major League Baseball’s Joint Drug Prevention and Treatment Program",
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      "title": "Press release: MLB new guidance against use of foreign substances",
      "url": "https://www.mlb.com/press-release/press-release-mlb-new-guidance-against-use-of-foreign-substances"
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    {
      "title": "Baseball in Japan",
      "url": "https://faq.japan-travel.jnto.go.jp/en/guide/japan-baseball/"
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    {
      "title": "Baseball scorekeeping",
      "url": "https://en.wikipedia.org/wiki/Baseball_scorekeeping"
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    {
      "title": "Take me out to the ballgame (and then to court)",
      "url": "https://prologue.blogs.archives.gov/2012/07/09/take-me-out-to-the-ballgame-and-then-to-court/"
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    {
      "title": "“Take Me Out to the Ball Game”",
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    {
      "title": "John Miley’s Passion For Sports",
      "url": "https://loc.gov/loc/lcib/1105/sports.html"
    },
    {
      "title": "The First Publication of “Casey at the Bat”",
      "url": "https://blogs.loc.gov/catbird/2013/06/the-first-publication-of-casey-at-the-bat/"
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    {
      "title": "Norman Rockwell’s Umpire Paintings",
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  "license": "https://creativecommons.org/licenses/by/4.0/"
}