Double-elimination tournament

A double-elimination tournament is a type of elimination tournament competition in which a participant ceases to be eligible to win the tournament's championship upon having lost two games or matches. It stands in contrast to a single-elimination tournament, in which only one defeat results in elimination.

One method of arranging a double-elimination tournament is to break the competitors into two sets of brackets, the winners bracket and losers bracket (W and L brackets for short; also sometimes upper bracket and lower bracket, respectively) after the first round. The first-round winners proceed into the W bracket and the losers proceed into the L bracket. The W bracket is conducted in the same manner as a single-elimination tournament, except that the losers of each round "drop down" into the L bracket. Another method of double-elimination tournament management is the Draw and Process.

As with single-elimination tournaments, most often the number of competitors is equal to a power of two (8, 16, 32, etc.) so that in each round there is an even number of competitors and never any byes. The maximum number of games in a double-elimination tournament is one less than twice the number of teams participating (e.g., 8 teams – 15 games). The minimum number is two less than twice the number of teams (e.g., 8 teams – 14 games).

If the bracket arrangement is being used then each round of the L Bracket is conducted in two stages; a minor stage followed by a major stage. Both contain the same number of matches (assuming there are no byes) which is the same again as the number of matches in the corresponding round of the W Bracket. If the minor stage of an L Bracket round contains N matches, it will produce N winners. Meanwhile, the N matches in the corresponding round of the W Bracket will produce N losers. These 2N competitors will then pair off in the N matches of the corresponding major stage of the L Bracket.

For example, in an eight-competitor double-elimination tournament, the four losers of the first round, W Bracket quarter finals, pair off in the first stage of the L Bracket, the L Bracket minor semifinals. The two losers are eliminated, while the two winners proceed to the L Bracket major semifinals. Here, those two players/teams will each compete against a loser of the W Bracket semifinal in the L Bracket major semifinals. The winners of the L Bracket major semifinals compete against each other in the L Bracket minor-final, with the winner playing the loser of the W Bracket final in the L Bracket major final.

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