# Double elimination tournaments

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So I want to host a double elimination tournament. I know that you have to lose twice to be eliminated, and that there’s a winners and a losers bracket. But I don’t really understand how it works, especially with its matchups. Reading its Wikipedia article made me even more confused…there’s “minor” and “major” loser rounds?

In:

It’s not too difficult, but I understand if the confusion.

Teams plays. If they win they stay in a winner’s bracket. If they lose they move down to a loser’s bracket. If you lose twice you are out.

A plays B. B Loses.

C plays D. D Loses.

B then plays D. B wins and D is out.

A then plays C. C Loses.

C then plays B. C wins. B is out.

A plays C. If A wins. They win it all.

If C wins, they play again. Winner takes all.

The way that I have operated in the past is like this:

Everyone starts in the “winners” bracket. If you lose in the first round of the winner’s bracket, you are placed in the first round of the loser’s bracket. If you win the first round of the winner’s bracket, you advance to the second round of the winner’s bracket.

Now, everyone in the first round of the loser’s bracket competes against each other. If you lose here, you’re out. If you win, you advance to the second round of the loser’s bracket.

Back to the winners. The second round competes. The winners of the second round of the winners’ bracket advance to round W3 (Winners’ 3rd). The losers of W2 (Winners’ 2nd) are relegated to L2 (Losers’ 2nd).

Now back to the losers. The winners of L1 (Losers’ 1st) compete against the newly relegated players (losers of W2) in L2 (Losers’ 2nd). Winners of L2 advance to L3, while losers of L2 are eliminated.

Continue this back and forth until you have an ultimate winner (who has never lost a game) and an ultimate loser (who has lost exactly one game). They now compete against each other.

If the ultimate winner wins, the ultimate loser has lost **twice** and is eliminated. If the ultimate loser wins, the ultimate winner has lost **once**, so they have to play again. The ultimate winner must lose **two** games in the finale in order to be eliminated, in order to be fair.

Forget all that, double elminiation is actually super easy. You have a winners bracket: Teams that have not lost. And a loser’s bracket: Teams with 1 loss.

All teams start in the winners brack (i.e. no losses). All winning teams stay. All losing teams go to the losers bracket. A next round goes. Winning teams play other winning teams, losers play losers.

A team in the losers bracket who wins, stays alive. A team in the losers brack who loses, is out. The winner of the losers match, plays the loser of the winners match. The winners bracket now consists again of only teams that have not loss.

This continues. Until only 2 teams remain, which is what makes this style unique.

One of those teams is still in the winners brackets and one is in the losers brack. Remember, this is double elimination. You must lose TWICE to get kicked out. That means the finals are unbalanced. The winner-bracket team only needs to win once to win the tournament, but the loser-bracket team must win twice, because the winners bracket team still gets its two losses.

Double elimination tournaments are really good for allowing the “best” teams to reach the final stages of the tournament and to avoid a case where two top teams play each other early and one gets eliminated, and thus could have for example, the final game being between the top team and a team that isn’t as good, as maybe the top team knocked out all of the other good teams. Double elimination allows teams to keep going, so that in the end you are much more likely to have the two best teams playing

The “double” in the name means that a team is eliminated after it loses twice. All teams start in the winners’ bracket, which has only the teams that have not lost yet. When a team loses once, it moves to the losers’ bracket, which has only the teams that have lost once. When a team in the losers’ bracket loses again, it is eliminated from the tournament.

When the tournament is down to one team in the winners’ bracket and one team in the losers’ bracket, different variations of double-elimination tournaments proceed differently. I’m guessing that’s what the major and minor loser rounds refer to. (I have not heard those terms before.)

The part about choosing which teams play each other is separate from the tournament structure. It’s common to have, say 1-16, 2-15, 3-14, and so on in the first round of matches. But when teams move to the losers’ bracket, the choice of teams in each match becomes complex because it’s desirable to not have the same two teams meet in the winners’ bracket and the losers’ bracket if it can be avoided.

It would probably be helpful to go to [Challonge](http://challonge.com) and make some brackets and play around with them. That might be more ELI5 than us describing seeding algorithms in words.