Perfect games

A perfect game is defined by Major League Baseball as a game in which a pitcher (or combination of pitchers) pitches a victory that lasts a minimum of nine innings and in which no opposing player reaches a base. Thus, the pitcher (or pitchers) cannot allow any hits, walks, hit batsmen, or any opposing player to reach base safely for any other reason: in short, "27 up, 27 down". The feat has been achieved 23 times in MLB history – 21 times since the modern era began in 1900, most recently by Félix Hernández of the Seattle Mariners on August 15, 2012.

A perfect game is also a no-hitter and a shutout. A fielding error that does not allow a batter to reach base, such as a misplayed foul ball, does not spoil a perfect game. Weather-shortened contests in which a team has no baserunners and games in which a team reaches first base only in extra innings do not qualify as perfect games under the present definition. The first confirmed use of the term "perfect game" was in 1908; the term's current definition was formalized in 1991. Although it is possible for multiple pitchers to combine for a perfect game (as has happened 11 times at the major league level for a no-hitter), to date, every major league perfect game has been thrown by a single pitcher. In Nippon Professional Baseball, no-hitters or perfect games that use two or more pitchers are considered unofficial.

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