In baseball, throwing a perfect game is a pitching accomplishment in which one or more pitchers does not allow a baserunner on base over the course of one game. In Nippon Professional Baseball, a perfect game is an extremely rare occurrence, only occurring 16 times.
Unlike in Major League Baseball (MLB), combined perfect games are not considered as official perfect games by Nippon Professional Baseball.
In Game 5 of the 2007 Japan Series, a rare combined perfect game occurred. However, it is not recognized as such since no-hitters or perfect games achieved by multiple pitchers in one game are considered unofficial by NPB. However, it is recognized by the World Baseball Softball Confederation (WBSC), the international governing body of baseball, as a perfect game.