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Sonneborn-Berger
Keywords: Rules, Tournament
Sonneborn-Berger is a method to determine a tournament result if two players have an equal number of wins. It takes the opponents' strength into account. Example: Each player has played two games against each other player. 1 indicates a win, 0 a loss. +---------+---------+------------------+--------------+ | 1st | 2nd | won games | Sonneborn- | | round | round | | Berger | |---------+---------| | | | A B C D | A B C D | score | opponent | score | +---+---------+---------+-------+----------+--------------| | A | - 1 1 1 | - 0 1 0 | 4 | B C C D | 4+3+3+1 = 11 | | B | 0 - 1 1 | 1 - 0 1 | 4 | A C D D | 4+3+1+1 = 9 | | C | 0 0 - 1 | 0 1 - 1 | 3 | B D D | 4+1+1 = 6 | | D | 0 0 0 - | 1 0 0 - | 1 | A | 4 = 4 | +---+---------+---------+-------+----------+--------------+ Player A and B both have 4 wins, thus the Sonneborn-Berger method is used to determine the tournament winner: For each won game the opponent's final primary score is added to the winner's Sonneborn-Berger score. For example, A won against B, C, C and D, his Sonneborn-Berger score is 4+3+3+1 = 11. B has a Sonneborn-Berger score of 9, thus A is the tournament winner. Related linksDiscussionDieter: Is this what we call SOS (Sum of Opponent's Scores?) in MacMahon ? SAS: No, it's what is sometimes called SODOS (Sum Of Defeated Opponents' Scores), at least in the absence of draws. SOS makes more sense than Sonneborn-Berger for McMahon tournaments. Sonneborn-Berger is mainly used for all-play-all tournaments, where SOS doesn't work at all. Tim Brent: There is also a modified version at Little Golem where the score is double the opponent's points (i.e. if second has 2 points and first won, the Sonneborn score is 4). This is a copy of the living page "Sonneborn-Berger" at Sensei's Library. ![]() |