Swiss-system tournament

A Swiss-system tournament is a competition format in which contestants are paired using rules designed to ensure that each competitor plays opponents with a similar running score without playing the same opponent more than once. Match pairing for each round is done after the previous round has ended and depends on its results. The winner is the competitor with the highest aggregate points earned in all rounds. With an even number of participants, all competitors play in each round. It contrasts with an elimination tournament, where not all participants play in later rounds, as well as with round-robin tournaments, where each competitor plays every possible opponent.

The Swiss system is used for competitions in which it is undesirable to eliminate any competitors before the end of the tournament, but which have too many entrants to make a full round-robin (all-play-all) feasible. In contrast, all-play-all is suitable if there are a small number of competitors. The Swiss system seeks to provide a clear winner among a large number of competitors within a relatively small number of rounds of competition, while avoiding the situation in single-elimination (knockout) tournaments in which a single bad result can remove a good competitor.