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Placement in go tournaments

Placement is based on Number of wins (Swiss tournaments) or on Mac-Mahon score (Mac-Mahon tournaments). When tie-breaks are necessary, the most frequent criteria are listed below:

SOS, SOSOS and SODOS

Very popular in Mac-Mahon tournaments

  • SOS : Sum of Opponents Scores.
    The Scores in question are usually Mac-Mahon scores
    The score that is taken in account is the score at calculation time (and not at game time)
  • SOSOS : Sum of Opponents SOS
  • SODOS : Sum of Defeated Opponents scores
Opponent's score is corrected with the the handicap if any.
ExT, ExR

Exploits Tentés, Exploits Réussis
The idea is to take in account the difficulty of the game. A game is assumed to be difficult for a player if the actual handicap (AH) was, for that player, more difficult than Natural Handicap (NH)

  • if AH < NH, then coef = 0 (easy game)
  • if AH = NH, then coef = 1 (normal game)
  • if AH = NH +1 then coef = 2 ( difficult game)
  • if AH >= NH +2 then coef = 3 (very difficult game)

ET is the sum of opponents scores, with coef as a weight factor
ER is the sum of defeated opponents scores, with coef as a weight factor

CUSS

CUmulative Sum of Scores
CUSS after round 1 is the score of the player himself
CUSS after round 2 is the CUSS of round 1 plus the score of the player himself after round 2
CUSS after round n is the CUSS of round n-1 plus the score of the player himself after round n
The idea is that, in most pairing systems, it is a better performance to win the former games and lose the last one than to lose the first game and win the other ones.
An other positive argument in CUSS favour is that it does not depend on the opponents behaviour after the game.

Dir

Direct Confrontation
If one player has won against all the other players with the same score and lost against no one, then Dir = 1 for this player and Dir = 0 for the other players.
If no player maches the above condition, then Dir = 0 for all the players of the group