A McMahon system tournament is a special type of Swiss system tournament, used for games such as go, chess, etc. In a Swiss tournament, all players compete in the same number of rounds against various other players, according to pairings determined by the tournament organizers, and gain a point for each round they win. The player with the highest resulting is the tournament winner, with various tie-breaking systems. In a McMahon tournament, players additionally begin with points based on their entry rank, so that stronger players begin with more points and are thus more likely to win the tournament. E.g. a 2 dan would begin with one point more than a 1 dan. There is often an upper and/or lower bar, so that players at the high or low end are treated equally for beginning points. The system is named after Lee McMahon of New York Go Club, where it was originally used for club rankings. It was then adopted for tournaments in Britain. Use of the McMahon system does not determine policy on other tournament questions such as whether to pair players from the same clubs, whether to use accelerated ratings, whether go games should be even or handicap, etc.
