The American League Championship Series (ALCS) is a best-of-seven playoff and one of two League Championship Series comprising the penultimate round of Major League Baseballs (MLB) postseason. It is contested by the two winners of the American League (AL) Division Series. The winner of the ALCS wins the AL pennant and advances to the World Series, MLBs championship series, to play the winner of the National Leagues (NL) Championship Series. The ALCS began in 1969 as a best-of-five playoff and used this format until 1985, when it changed to its current best-of-seven format. The ALCS started in 1969, when the AL reorganized into two divisions, East and West. The winners of each division played each other in a best-of-five series to determine who would advance to the World Series. In 1985, the format changed to best-of-seven. In 1994, the league was restructured into three divisions, with the three division winners and a Wild Card team advancing to a best-of-five postseason round, known as the American League Division Series (ALDS). The winners of that round then advanced to the best-of-seven ALCS.