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 referred to as championship bracket and elimination bracket, upper bracket and lower bracket, or main bracket and repechage) 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 number of games in a double-elimination tournament is one or two less than twice the number of teams participating (e.g. 8 teams would see 14 or 15 games).

If the standard double-elimination 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.

The final round of a double-elimination tournament is usually set up to be a possible two games, with the second referred to as the "if game" or "bracket reset". In this structure, the L bracket finalist needs to win both games of the final round to be the tournament champion, while the W bracket finalist wins the tournament by winning either game of the final round. If the final round is scheduled as only a single game, as in the 2018 NCAA Beach Volleyball Championship, the W bracket finalist will be eliminated from the tournament if they lose this match, meaning the tournament is not truly a double-elimination tournament.

The double-elimination format has some advantages over the single-elimination format, most notably the fact that third and fourth places can be determined without the use of a consolation or "classification" match involving two contestants who have already been eliminated from winning the championship.