League Championship Series

The League Championship Series (LCS) is the official name for the semifinal round of postseason play in Major League Baseball which has been conducted since 1969. In 1981, and since 1995, the two annual series have matched up the winners of the Division Series, and the winners advance to meet in the World Series. The LCS comprises the American League Championship Series (ALCS) and National League Championship Series (NLCS).

The League Championship Series was promulgated in 1969, when both the National League and the American League increased in size from ten teams to twelve with the addition, via expansion, of the Montreal Expos and San Diego Padres to the former and the Kansas City Royals and Seattle Pilots (now the Milwaukee Brewers of the NL) to the latter. Concomitant with this, both leagues formed Eastern and Western Divisions, the first-place teams from which faced off in the LCS.

Originally, the League Championship Series were best-of-five using the 2–3 format in which the team without home field advantage hosted the first two games and the team with it hosted the remaining game(s), making it impossible for the disadvantage team to win the series at home. It also allowed those teams the unusual luxury of starting a series at home, possibly having home field advantage in a three-game series, and a guarantee that they play the maximum number of games possible at home (2).

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