From BR Bullpen
The Division Series are a 5-game postseason series that precedes the two League Championship Series and determines which two teams will face eachother for the league championship. Each year, there are two National League Division Series and two American League Division Series.
The first Division Series were played on a one-off basis in 1981 as a result of the 1981 Split Season Schedule. These opposed the first half and second half winners in each of the four divisions which existed at the time.
The first "permanent" Division series were scheduled in 1994, after the reorganization of each major league into three divisions and the introduction of the Wild Card. The first Division Series under this format were cancelled when the 1994 strike wiped out the entire 1994 Postseason. As a result, the Series were first played in 1995.
There are four Division Series, two in each league. Starting in 2012, the division winner with the best record plays the wild card team which won the Wild Card Game between the two wild card teams; the other two division winners play eachother. During the period when there was only one wild card team in each league, from 1995 to 2011, that team was prevented from meeting a team from its own division in the Division Series, and as a result played the division winner with the second-best overall record. This changed when the format with two wild card teams was introduced.
By convention, the Division Series featuring the team with the best overall record in the league is considered the first division series, and the other one is the second.
 National League Division Series
 American League Division Series
 Related Sites
|Major League Baseball National League Division Series
|Major League Baseball American League Division Series