Swiss system

The Swiss system makes it possible to run a tournament with many participants without having everyone play everyone else. The number of rounds is declared in advance, and new pairings after each round depend on the scores accumulated so far.

The central idea is to pair players with equal or similar scores whenever possible. If a score group cannot be paired completely, some players may need opponents from a different score group. The rules also prevent two participants from meeting more than once and try to manage colors fairly, meaning who receives White and who receives Black.

With an odd number of participants, one player may receive a pairing-allocated bye, a round without an opponent for which the regulations assign a score. After the final round, standings are based on points, and ties may be separated by methods such as Buchholz or other tie-breaks specified by the event.

Unlike a round-robin, a Swiss tournament does not create a direct game between every pair of players. Its practical advantage is that a large field can compete in a manageable number of rounds. The International Chess Federation (FIDE) recognizes several specific Swiss pairing systems, so 'Swiss system' names a family of procedures rather than one single pairing table.