Chess tournament
A Swiss system event. Permits large entries, and is the most common format. The event has a pre-set number of rounds, and there are many more players than rounds. Progressively, players play opponents with roughly similar points to their own score. Players who win get stronger opponents, players who lose get weaker opponents. Pairing each round may be done by computer. This is an invention of the chess world and, like chess clocks, has been adopted by a number of other two-person sports.