The best of 7 game format is one of the most common used in playoff formats.  In the case of the World Series, the 7 game format has led to a long list of memorable finishes, decided in the final and all-important game.  The 7 game format was not always in use however and was not introduced until after 1920.

On this day, December 20th, in 1921, a judge decided that baseball’s World Series should be a best of 7 series. Prior to the ruling, the World Series was played in numerous format, the most recent being a best-five-of-nine series.

The 1922 World Series was the first to be played in the current format with the New York Giants sweeping the Yankees four games to none.