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Baseball · Official Rules of Baseball

Law 6: Definition of Terms

3 parts · 5 tests · 50 facts · updated 27 October 2026 · markdown

The words the rules are written in: balls, strikes and the strike zone, the pitcher's terms, fair and foul balls, catches and the infield fly, double plays, interference, obstruction, substitutes and the run difference rule.

6.61Pitches, Strikes and Balls

The strike zone, balls and strikes, the half swing, and the pitcher's terms from the balk to the set position.

Test 1Balls, strikes and the strike zoneTake a test

  1. A pitch that touches the ground and bounces through the strike zone is a ball.

    Source: WBSC ORB 2025-2026, Rule 6.3 · applied

  2. The zone runs from the midpoint between the top of the shoulders and the top of the pants down to the bottom of the kneecaps.

    Source: WBSC ORB 2025-2026, Rule 6.78 · recall

  3. Unlike MLB's pure judgement, the WBSC rule sets a test: a half swing is a strike if the barrel head passes the front hip.

    Source: WBSC ORB 2025-2026, Rule 6.38 · recall

  4. If the batter swings at a pitch that struck the ground in front of him, it is a strike if he misses and in play if he hits it.

    Source: WBSC ORB 2025-2026, Rule 6.77.2 · applied

  5. A foul not caught counts as a strike only while the batter has fewer than two strikes.

    Source: WBSC ORB 2025-2026, Rule 6.77.3 · applied

  6. An attempted bunt that goes foul and is not legally caught is a strike, whatever the count, so here it is strike three.

    Source: WBSC ORB 2025-2026, Rule 6.77.4 · applied

  7. A pitch in the zone that touches the batter is a strike; the ball is dead, no runner advances and he does not take first.

    Source: WBSC ORB 2025-2026, Rule 6.77.5 · applied

  8. Shoulders first; the upper edge of the zone next; then the waistband of the pants; the kneecaps lowest.

    Source: WBSC ORB 2025-2026, Rule 6.78 · recall

  9. A base on balls is also awarded when the opposing manager signals the plate umpire for an intentional walk; no pitches are needed.

    Source: WBSC ORB 2025-2026, Rule 6.6 · recall

  10. Any part of the ball passing over the plate between the bottom of the kneecaps and the top of the zone is a strike, judged as it crosses the plate.

    Source: WBSC ORB 2025-2026, Rule 6.77.2, 6.78 · applied

Test 2The pitcher's termsTake a test

  1. A balk is an illegal act by the pitcher while there are runners on base.

    Source: WBSC ORB 2025-2026, Rule 6.2 · recall

  2. On a balk every runner moves up one base.

    Source: WBSC ORB 2025-2026, Rule 6.2 · recall

  3. The battery is the pitcher and the catcher.

    Source: WBSC ORB 2025-2026, Rule 6.10 · recall

  4. The pivot foot is the one on the rubber as the pitch is delivered: the left foot for a left-hander, the right for a right-hander.

    Source: WBSC ORB 2025-2026, Rule 6.66 · recall

  5. A quick pitch is an illegal pitch with the obvious intent of catching the batter off balance.

    Source: WBSC ORB 2025-2026, Rule 6.68 · recall

  6. A pitch without the pivot foot on the rubber is an illegal pitch, and with runners on base an illegal pitch is a balk.

    Source: WBSC ORB 2025-2026, Rule 6.41 · applied

  7. A wild pitch is so high, low or wide that the catcher cannot handle it with ordinary effort; a catchable ball he misses is not one.

    Source: WBSC ORB 2025-2026, Rule 6.88 · recall

  8. In the set position the time of pitch is when he begins his natural motion after coming set with both hands together.

    Source: WBSC ORB 2025-2026, Rule 6.75, 6.85.2 · recall

  9. Within an at-bat a pitcher may notify the umpire of a switch to the windup only after a runner advances or an offensive substitution.

    Source: WBSC ORB 2025-2026, Rule 6.75 · applied

  10. With runners on, a pitcher standing like this is presumed to be in the set position unless he told the umpire he would use the windup.

    Source: WBSC ORB 2025-2026, Rule 6.75 · applied

6.62Batted Balls and Catches

Fair and foul balls, kinds of batted ball, in flight, the catch and the infield fly.

Test 1Fair balls, foul balls and batted ballsTake a test

  1. A ball that first falls on fair ground on or beyond first or third base is fair, wherever it rolls afterwards.

    Source: WBSC ORB 2025-2026, Rule 6.26.3 · applied

  2. A batted ball off the pitcher's rubber that rebounds untouched into foul territory between home and first or third is foul.

    Source: WBSC ORB 2025-2026, Rule 6.34.6 · applied

  3. A fly is judged by the position of the ball relative to the foul line, not by whether the fielder is on fair or foul ground.

    Source: WBSC ORB 2025-2026, Rule 6.26.4 · recall

  4. A ball that hits the top of the fence in fair territory and bounces over is a home run.

    Source: WBSC ORB 2025-2026, Rule 6.26.6 · applied

  5. A batted ball that hits the ground or plate and then the batter in the box is foul.

    Source: WBSC ORB 2025-2026, Rule 6.34.5 · applied

  6. A line drive goes sharp and direct from the bat to a fielder without touching the ground.

    Source: WBSC ORB 2025-2026, Rule 6.51 · recall

  7. A ball is in flight until it touches the ground or an object other than a player; an umpire is not a player.

    Source: WBSC ORB 2025-2026, Rule 6.43 · applied

  8. From U-15 up, the three-foot lane covers the last 45 feet to first base; the foul pole stands at the fence beyond it.

    Source: WBSC ORB 2025-2026, Rule 2.1 · recall

  9. A foul tip goes sharp and direct from the bat to the catcher and is legally caught; it is a strike and the ball stays alive.

    Source: WBSC ORB 2025-2026, Rule 6.36 · recall

  10. A ball that settles on foul ground between home plate and first base is foul, even if it bounced in fair territory first.

    Source: WBSC ORB 2025-2026, Rule 6.34.1 · applied

Test 2Catches and the infield flyTake a test

  1. A catch requires the fielder to hold the ball long enough to show complete control.

    Source: WBSC ORB 2025-2026, Rule 6.15 · recall

  2. A catch stands when a fielder ends up with secure possession, even after another fielder touched or juggled it, if no offensive player or umpire touched it.

    Source: WBSC ORB 2025-2026, Rule 6.15 · applied

  3. It is not a catch if the fielder is touching dead-ball territory when he makes it.

    Source: WBSC ORB 2025-2026, Rule 6.15 · applied

  4. An infield fly needs runners on first and second, or the bases loaded, before two are out.

    Source: WBSC ORB 2025-2026, Rule 6.45 · recall

  5. The infield fly rule covers a fair fly, not including a line drive or an attempted bunt.

    Source: WBSC ORB 2025-2026, Rule 6.45 · recall

  6. If the ball is near the baselines the umpire adds 'If Fair', because its status depends on where it ends up.

    Source: WBSC ORB 2025-2026, Rule 6.45 · recall

  7. Ordinary effort is what a fielder of average skill at that position should do, allowing for field and weather conditions.

    Source: WBSC ORB 2025-2026, Rule 6.57 · recall

  8. A declared infield fly that falls outside the base line but bounces fair before passing first or third base is an infield fly.

    Source: WBSC ORB 2025-2026, Rule 6.45 · applied

  9. The ball stays alive; as on any fly, runners may retouch and advance once the ball has been touched.

    Source: WBSC ORB 2025-2026, Rule 6.45 · recall

  10. If a fielder catches the ball and drops it while attempting a throw, it is still a catch.

    Source: WBSC ORB 2025-2026, Rule 6.15 · applied

6.63Plays and People

Double and triple plays, the fielder's choice, interference and obstruction, substitutes and the run difference rule.

Test 1Plays and the people in themTake a test

  1. A double play puts two offensive players out as a result of continuous action, with no error between the putouts.

    Source: WBSC ORB 2025-2026, Rule 6.23 · recall

  2. In a force double play both putouts are force outs; in a reverse one the first is a force and the second a tag.

    Source: WBSC ORB 2025-2026, Rule 6.23.1 · recall

  3. A fielder's choice is playing a fair grounder to retire another runner rather than throwing to first for the batter-runner.

    Source: WBSC ORB 2025-2026, Rule 6.29 · applied

  4. Defensive interference is a fielder, usually the catcher, hindering or preventing the batter from hitting a pitch.

    Source: WBSC ORB 2025-2026, Rule 6.48.2 · recall

  5. A pinch runner is an eligible substitute, not in the line-up, who runs for a player listed in it.

    Source: WBSC ORB 2025-2026, Rule 6.63 · recall

  6. A disqualified player is no longer eligible but has not been ejected, for example an injured or a substituted player.

    Source: WBSC ORB 2025-2026, Rule 6.22 · recall

  7. A team losing by ten or more runs after batting at least five innings ends the game; U-12 also has fifteen after four.

    Source: WBSC ORB 2025-2026, Rule 6.71.2 · recall

  8. A run down can end with no out, a force out is one, a double play two and a triple play three.

    Source: WBSC ORB 2025-2026, Rule 6.72, 6.23, 6.87 · recall

  9. The first out is a force at third; that removes the force at home, so the second out needs a tag: a reverse double play.

    Source: WBSC ORB 2025-2026, Rule 6.23.2 · applied

  10. Obstruction is a fielder who, not holding the ball and not fielding it, impedes the progress of a runner.

    Source: WBSC ORB 2025-2026, Rule 6.54 · applied

Sources

WBSC Official Rules of Baseball 2025-2026, Rule 6 (paraphrased in original wording; original questions authored from the Rules, not reproduced)

  • WBSC ORB 2025-2026, Rule 6.455
  • WBSC ORB 2025-2026, Rule 6.154
  • WBSC ORB 2025-2026, Rule 6.782
  • WBSC ORB 2025-2026, Rule 6.22
  • WBSC ORB 2025-2026, Rule 6.752
  • WBSC ORB 2025-2026, Rule 6.31
  • WBSC ORB 2025-2026, Rule 6.381
  • WBSC ORB 2025-2026, Rule 6.77.21
  • WBSC ORB 2025-2026, Rule 6.77.31
  • WBSC ORB 2025-2026, Rule 6.77.41
  • WBSC ORB 2025-2026, Rule 6.77.51
  • WBSC ORB 2025-2026, Rule 6.61
  • WBSC ORB 2025-2026, Rule 6.77.2, 6.781
  • WBSC ORB 2025-2026, Rule 6.101
  • WBSC ORB 2025-2026, Rule 6.661
  • WBSC ORB 2025-2026, Rule 6.681
  • WBSC ORB 2025-2026, Rule 6.411
  • WBSC ORB 2025-2026, Rule 6.881
  • WBSC ORB 2025-2026, Rule 6.75, 6.85.21
  • WBSC ORB 2025-2026, Rule 6.26.31
  • WBSC ORB 2025-2026, Rule 6.34.61
  • WBSC ORB 2025-2026, Rule 6.26.41
  • WBSC ORB 2025-2026, Rule 6.26.61
  • WBSC ORB 2025-2026, Rule 6.34.51
  • WBSC ORB 2025-2026, Rule 6.511
  • WBSC ORB 2025-2026, Rule 6.431
  • WBSC ORB 2025-2026, Rule 2.11
  • WBSC ORB 2025-2026, Rule 6.361
  • WBSC ORB 2025-2026, Rule 6.34.11
  • WBSC ORB 2025-2026, Rule 6.571
  • WBSC ORB 2025-2026, Rule 6.231
  • WBSC ORB 2025-2026, Rule 6.23.11
  • WBSC ORB 2025-2026, Rule 6.291
  • WBSC ORB 2025-2026, Rule 6.48.21
  • WBSC ORB 2025-2026, Rule 6.631
  • WBSC ORB 2025-2026, Rule 6.221
  • WBSC ORB 2025-2026, Rule 6.71.21
  • WBSC ORB 2025-2026, Rule 6.72, 6.23, 6.871
  • WBSC ORB 2025-2026, Rule 6.23.21
  • WBSC ORB 2025-2026, Rule 6.541