Now that the 162-game regular season has come to an end, the Major League Baseball (MLB) post season is in full swing. Five teams from the American and National Leagues are set to battle it out for the top trophy in sports. The winners of the American League Championship (ALCS) and the National League Championship (NLCS) will meet at the end of October and play each other in the best-of-seven World Series.

History
The first World Series was played in 1903 in a best-of-nine series between the American League and the National League. Two years later, the Series was scaled back to a best-of-seven game series. The AL and NL split into separate division in 1969 and the NLCS and ALCS was formed, and four teams from the division made the playoffs. In 1994, the league adopted a six-division alignment and another round of playoffs was added with the Division Series.

Wild Card
In 1994, MLB expanded both the American and National Leagues to include three subdivisions in each league. The East, Central and West divisions add one wild card team, teams with the best record who didn’t win their division, into the mix. In 2012 a second wild card team was added and a winner-take-all game is played between the two. The winner of the wild card then plays the number one seed in the Division Series.

Division Series (ALDS and NLDS)
The Division Series is the best-of-five series. The team in the division with the best overall record receives the top seed and home-field advantage throughout the series. They also host games 1, 2 and 5 and play the team that won the wild card game. The two remaining divisional champs play each other and home field advantage is given to the team with the second-best record. The winners of the series then face off in the League Championship Series.\

League Championship Series (ALCS and NLCS)
The winners of the Division Series advance to the best-of-seven League Championship where the team with the best record will have home field advantage. If the wild card team has the better record, the division championship will still get home field advantage. The team with home field advantage hosts games 1, 2, 6 and 7.

World Series
The winners of both the ALCS and the NLCS advance to the World Series. The best-of-seven series takes place at the end of October. Prior to the 2002 season, home field advantage alternated every year between the leagues. The rule change stated that the league that won the All-Star game is given home field advantage and hosts games 1, 2, 6 and 7. Currently the team with the best overall regular season record is given home field advantage thanks to a rule change in 2017. The first team to win 4 of 7 games wins the World Series!