Extra inning

Extra innings is the extension of a baseball or softball game in order to break a tie.

Ordinarily, a baseball game consists of nine innings (in softball and high school baseball games there are typically seven innings; in Little League, six), each of which is divided into halves: the visiting team bats first, after which the home team takes its turn at bat. However, if the score remains tied at the end of the regulation number of complete innings, the rules provide that "play shall continue until (1) the visiting team has scored more total runs than the home team at the end of a completed inning; or (2) the home team scores the winning run in an uncompleted inning."

The rules of the game, including the batting order, availability of substitute players and pitchers, etc., remain intact in extra innings. Managers must display caution to avoid using all their substitute players, in case the game reaches extensive extra innings. The rules call for a forfeiture if a team is unable to field a full team of nine players.

In Major League Baseball, home teams won about 52% of extra-inning games from 1957 to 2007. During this same time period, home teams have won about 54% of all baseball games. So while the home team has some advantage in extra-inning games, this advantage is less noticeable than the initial home-field advantage. Home teams tend to have the greatest advantage in run-scoring during the first 3 innings.

For the visiting team to win, it must score as many runs as possible in the first (or "top") half of the inning and then prevent the home team from tying or taking the lead in the second (or "bottom") half. Because it bats in the bottom half of an inning, a home team wins the game by taking the lead at any point in the final inning. Normally in such a situation, the moment the winning run scores for whatever reason (base hit, sacrifice, wild pitch), the game immediately ends and no other runs are allowed. The term for winning in this scenario is a "walk-off" win (as everyone can walk off the field as soon as the winning run is scored). The exception is if the winning hit is a walk-off home run; all runners on base and the batter must circle the bases on a home run, so all their runs count for the final score. Each extra inning simply repeats this scenario.

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Wikipedia