Each plate appearance consists of a series of pitches, in which the pitcher throws the ball towards home plate while a batter is standing in the batter's box
(either right or left). With each pitch, the batter must decide whether
to swing the bat at the ball in an attempt to hit it. The pitches
arrive quickly, so the decision to swing must be made in less than a tenth of a second, based on whether the ball is hittable and in the strike zone,
a region defined by the area directly above home plate and between the
hollow beneath the batter's knee and the midpoint between the top of the
shoulders and the top of the uniform pants. In addition to swinging at
the ball, a batter who wishes to put the ball in play may hold his bat
over home plate and attempt to tap a pitch lightly; this is called a bunt. Good bunting technique has been described as "catching the ball with the bat."
On any pitch, if the batter swings at the ball and misses, he is charged with a strike. If the batter does not swing, the home plate umpire judges whether the ball passed through the strike zone. If the ball, or any part of it, passed through the zone, it is ruled a strike; otherwise, it is called a ball. The number of balls and strikes thrown to the current batter is known as the count; the count is always given balls first (except in Japan, where it is reversed), then strikes (such as 3-2 or "three and two", also known as a "full count," which would be 3 balls and 2 strikes).
If the batter swings and makes contact with the ball, but does not put it in play in fair territory—a foul ball—he is charged with an additional strike, except when there are already two strikes. Thus, a foul ball with two strikes leaves the count unchanged. (However, a noted exception to this rule is that a ball bunted foul with two strikes is a strikeout.) If a pitch is batted foul or fair and a member of the defensive team is able to catch it, before the ball strikes the ground, the batter is declared out. In the event that a bat contacts the ball, but the ball continues sharply and directly to the catcher's mitt and is caught by the catcher, it is a foul tip, which is same as an ordinary strike.
When three strikes occur on a batter, it is a strikeout and the batter is automatically out unless the pitch is not caught by the catcher or if the pitch bounces before it is caught. It is then ruled an uncaught third strike, a violation of the third strike rule: If the catcher drops the third strike, the batter is permitted to attempt to advance to first base if there are two outs in the inning or if it is unoccupied. In this case, the batter is not out (although the pitcher is awarded a strikeout). The catcher can try to get the batter out by tagging him with the ball or throwing the ball to first base to put him out. (See Doug Eddings (2005 ALCS) and Mickey Owen (1941 World Series) for famous examples of dropped third strikes that dramatically altered the course of post-season series.)
On the fourth ball, it is called a walk, and the batter becomes a runner, and is entitled to advance to first base without risk of being put out, called a base on balls or a walk (abbreviated BB). If a pitch touches the batter (or the batter's clothes), the umpire declares a hit by pitch (abbreviated HBP) and the batter is awarded first base, unless the umpire determines that the ball was in the strike zone when it hit the batter, or that the batter did not attempt to avoid being hit. In practice, neither exception is ever called unless the batter obviously tries to get hit by the pitch; even standing still in the box will virtually always be overlooked, and the batter awarded first. In addition, if the batter swings at a pitch that hits him, it counts as a strike. If the catcher's mitt, catcher's mask, or any part of the catcher comes in contact with the batter and/or the batter's bat as the batter is attempting to hit a pitch, the batter is awarded first base, ruled "catcher's interference".
On any pitch, if the batter swings at the ball and misses, he is charged with a strike. If the batter does not swing, the home plate umpire judges whether the ball passed through the strike zone. If the ball, or any part of it, passed through the zone, it is ruled a strike; otherwise, it is called a ball. The number of balls and strikes thrown to the current batter is known as the count; the count is always given balls first (except in Japan, where it is reversed), then strikes (such as 3-2 or "three and two", also known as a "full count," which would be 3 balls and 2 strikes).
If the batter swings and makes contact with the ball, but does not put it in play in fair territory—a foul ball—he is charged with an additional strike, except when there are already two strikes. Thus, a foul ball with two strikes leaves the count unchanged. (However, a noted exception to this rule is that a ball bunted foul with two strikes is a strikeout.) If a pitch is batted foul or fair and a member of the defensive team is able to catch it, before the ball strikes the ground, the batter is declared out. In the event that a bat contacts the ball, but the ball continues sharply and directly to the catcher's mitt and is caught by the catcher, it is a foul tip, which is same as an ordinary strike.
When three strikes occur on a batter, it is a strikeout and the batter is automatically out unless the pitch is not caught by the catcher or if the pitch bounces before it is caught. It is then ruled an uncaught third strike, a violation of the third strike rule: If the catcher drops the third strike, the batter is permitted to attempt to advance to first base if there are two outs in the inning or if it is unoccupied. In this case, the batter is not out (although the pitcher is awarded a strikeout). The catcher can try to get the batter out by tagging him with the ball or throwing the ball to first base to put him out. (See Doug Eddings (2005 ALCS) and Mickey Owen (1941 World Series) for famous examples of dropped third strikes that dramatically altered the course of post-season series.)
On the fourth ball, it is called a walk, and the batter becomes a runner, and is entitled to advance to first base without risk of being put out, called a base on balls or a walk (abbreviated BB). If a pitch touches the batter (or the batter's clothes), the umpire declares a hit by pitch (abbreviated HBP) and the batter is awarded first base, unless the umpire determines that the ball was in the strike zone when it hit the batter, or that the batter did not attempt to avoid being hit. In practice, neither exception is ever called unless the batter obviously tries to get hit by the pitch; even standing still in the box will virtually always be overlooked, and the batter awarded first. In addition, if the batter swings at a pitch that hits him, it counts as a strike. If the catcher's mitt, catcher's mask, or any part of the catcher comes in contact with the batter and/or the batter's bat as the batter is attempting to hit a pitch, the batter is awarded first base, ruled "catcher's interference".