McMahon system tournament
Encyclopedia
A McMahon system tournament is a generalized case of the Swiss system tournament
, used for games such as go
and chess
.
Like a Swiss tournament, all players compete in the same number of rounds against various other players. Unlike Swiss, the players do not all start with zero points, but are awarded initial points based on their rating prior to the tournament. The system features an "upper bar", set to a specific rating, so that all players that are considered to have a chance to win the tournament start with the same (maximum) number of points.
Players are paired each round against an opponent that has an equal or almost equal number of points so far, and gain a point for each round they win or half a point for a draw. The player with the highest number of points after the last round is the tournament winner, with various tie-breaking systems.
The system is named after Lee McMahon
of Bell Labs
, and was originally used as a club ranking system at the New York Go Club. It was then adopted for go tournaments in Britain, and has since become the most popular tournament system used in Go. Use of the McMahon system does not determine policy on other tournament questions such as whether to pair players from the same club, whether to use accelerated pairings, whether Go games should be even or handicap, etc.
The advantage of the McMahon system over the Swiss system is that it requires fewer rounds to find a winner, and that it avoids extreme match-ups (very strong players against very weak players) in the earlier rounds. By matching up possible tournament winners earlier, the system allows for more games amongst this group, and thus improves sampling.
Swiss system tournament
A Swiss-system tournament is a commonly used type of tournament where players or teams need to be paired to face each other for several rounds of competition. This type of tournament was first used in a Zurich chess tournament in 1895, hence the name "Swiss system". The Swiss system is used when...
, used for games such as go
Go (board game)
Go , is an ancient board game for two players that originated in China more than 2,000 years ago...
and chess
Chess
Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...
.
Like a Swiss tournament, all players compete in the same number of rounds against various other players. Unlike Swiss, the players do not all start with zero points, but are awarded initial points based on their rating prior to the tournament. The system features an "upper bar", set to a specific rating, so that all players that are considered to have a chance to win the tournament start with the same (maximum) number of points.
Players are paired each round against an opponent that has an equal or almost equal number of points so far, and gain a point for each round they win or half a point for a draw. The player with the highest number of points after the last round is the tournament winner, with various tie-breaking systems.
The system is named after Lee McMahon
Lee E. McMahon
Lee E. McMahon was an American computer scientist. He was a graduate of St. Louis University and obtained a Ph.D. in Psychology at Harvard. He worked for Bell labs from 1963 until 1989, and is best known for his contributions to early versions of the Unix operating system, in particular the sed...
of Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
, and was originally used as a club ranking system at the New York Go Club. It was then adopted for go tournaments in Britain, and has since become the most popular tournament system used in Go. Use of the McMahon system does not determine policy on other tournament questions such as whether to pair players from the same club, whether to use accelerated pairings, whether Go games should be even or handicap, etc.
The advantage of the McMahon system over the Swiss system is that it requires fewer rounds to find a winner, and that it avoids extreme match-ups (very strong players against very weak players) in the earlier rounds. By matching up possible tournament winners earlier, the system allows for more games amongst this group, and thus improves sampling.