EGF Tournament System Rules

Tournament Systems

The most frequently used tournament systems for a tournament or one of its stages are:
  • McMahon
  • Swiss
  • knockout
  • league
  • match
McMahon is the default. A tournament system can specify a seeding. A tournament can be part of a series of tournaments or have similar effects. For special purposes, well-defined combinations of different systems can be derived.

Top Bar

  • In a McMahon, the number of players above the top bar depends on the number rounds, should not be so small to exclude a likely winner, and should not be so big to let the winner greatly depend on the opponents' strengths.
  • By default, a supergroup is not used.
  • A tournament's Particular Tournament Rules may have a supergroup or otherwise special groups dealing with a great number of players.

Game Result

General

  • For his game, a player receives one of the values below, whichever has the most appropriate of the listed reasons.
  • If a tournament system accumulates such values over several rounds, then the value below is the current round's increment. As an exception, in a Swiss or McMahon, a player's accumulated values are rounded down; this also affects all tiebreakers.
  • In a McMahon, a player's McMahon Score is increased; in other tournament systems, a player's Number of Wins Score is increased.
  • In case of pairgo or rengo, "player" denotes a pair or team. In case of a team tournament round, a team's sum of game results are compared with the opposing team's sum of game results: The increment of a team's Number of Wins Score is 1 for the team with the greater sum, 0 for the opposing team, 1/2 if the sums are equal.
  • In exceptional circumstances, arbitration might assign appropriate other combinations of default results.

1

  • win due to the rules of play
  • win due to the opponent's loss on time
  • win due to the opponent's resignation
  • default win due to the opponent Bye
  • default win due to absent or late opponent
  • default win by the opponent's default loss due to arbitration

1/2

  • tie for both players due to the rules of play
  • default tie for both players due to arbitration
  • The player does not play in a round of McMahon or Swiss and this is in agreement to all valid tournament rulesets.

0

  • loss due to the rules of play
  • loss on time
  • loss by resignation
  • default loss due to absence or delay of both players
  • default loss due to absence or delay of the player
  • default loss of the player due to arbitration

Equal Players

In the final results list, players can be equal if tiebreakers are not used at all or if they are not broken by further tiebreakers. By default, the following applies to equal players:
  • They have the same place number, which is one greater than the number of better placed players.
  • Each of them receives the title issued for their place number.
  • By default, each of them receives the same amount if there are money prizes. They equally share the sum of all money prizes issued for those place numbers that they would have got if they were not equal. Other divisible prizes like, e.g., points accumulated in a series of tournaments, are distributed similarly.
  • Indivisible prizes like seeding places or flight tickets are issued by tiebreakers even if otherwise equal players share place number, title, or divisible prizes.

Tiebreakers

General

Tiebreakers might be used for none, one, or several of these purposes:
  • ordering the players in the final result list
  • distributing otherwise indivisible prizes
  • ordering the players for making pairings
  • determining seeded players
Different tiebreakers might be used for different purposes. Pairing programs should allow such.

If only one tiebreaker is used, then these tiebreakers are recommended:

  • Number of Board Wins.
  • Direct Comparison.
  • SOS-2.
  • SOS-1.
  • SOS.
  • Rating.
  • Previous Order.
  • Lottery.
More than one tiebreaker might be used in a relative order of priority.

Only in tournaments with a special system, other tiebreakers may be used. E.g., in a combined groups and KO system, a global tiebreaker might be used after the per-group tiebreakers and before Lottery.

Definition of Direct Comparison

  • A player's Direct Comparison is the Number of Wins Score of only the games played against each other.
  • If it results in a finer tiebreaking, then the definition is applied iteratively: If an application still ties some players, then for them the tiebreaker is applied again, not overwriting but fine-tuning its previous application. This is sometimes possible if four or more players are tied before the first application of Direct Comparison.
  • However, in a McMahon or Swiss tournament or same stage of a tournament, the above definition of Direct Comparison is overridden by giving each player of mutually tied players the value 0 if they all have not played the same number of games against each other.

Definition of Other Tiebreakers

  • Number of Board Wins = Sum of a team's game results in all rounds.
  • SOS = Sum of opponents' scores, which are the McMahon scores in a McMahon or the Number of Wins Scores in a Swiss.
  • SOS-1 = SOS, where 1 round with the smallest value is ignored.
  • SOS-2 = SOS, where 2 rounds with the smallest values are ignored.
  • Rating = EGF-rating just before the tournament's start.
  • Previous Order = relative order of the players at a specified earlier time like during the qualification or the previous tournament.
  • Lottery = For the mutually tied players, there is one lot for each of them. Then as many lots as necessary are drawn in order. This determines those players' relative order.

The Effect of Unplayed Games

To a player's SOS, SOS-1, or SOS-2 in a round without an opponent or with the opponent Bye, in a McMahon his own start McMahon Score is added and in a Swiss 0 is added.

Recommended Order of Equal Players or Tiebreakers

  • This general order of priority is recommended:
    1. Playing more rounds.
    2. Playing playoff rounds, possibly with short thinking times.
    3. Having equal players.
    4. Using tiebreakers.
  • If only one tiebreaker is used, then the recommended order of priority is given by the list of tiebreakers that may be used.
  • Only one of SOS-2, SOS-1, or SOS may be used.
  • If more than one tiebreaker is used in a relative order of priority, then this is given by the relative order in the list of tiebreakers that may be used.

Recommended Usage of Tiebreakers

  • Number of Board Wins: It can be applied only in a team tournament. There it is highly meaningful and should be the first tiebreaker.
  • Direct Comparison: Provided it can be applied at all, it is very meaningful because it might be interpreted as an already performed knockout playoff among the tied players. So, for the final results, generally it should be the first or even the only tiebreaker.
  • SOS-2, SOS-1, SOS: They should be used only in McMahon or Swiss. They express a mixture of opponents' strength, statistical noise, and pairing luck. Their apparent numerical precision is greater than their true significance. Therefore they must be used with care. Application for the final results is doubtful while application for making pairings is reasonable. SOS-2 filters more noise than SOS-1 than SOS; more noise can be filtered in more rounds more easily.
  • Rating. It expresses the players' relative strength just before the tournament's start. Its apparent numerical precision is much greater than its true significance. For players with similar ratings it behaves like lottery - for high dan players with significantly different ratings it is reasonably meaningful. Hence it can be applied just before lottery especially for seeding a great number of high dan players.
  • Previous Order: If it refers to a previous tournament, this information is the more meaningful the more recently that tournament was played. It should be used for similar purposes as rating.
  • Lottery: It should be used only as the last tiebreaker and if any other tiebreaker cannot make more meaningful decisions.
  • Global tiebreaker: In special tournament systems, it might be more meaningful than lottery if it fits the tournament system well and is defined carefully.
For the final results of a McMahon or Swiss, tiebreakers should be considered meaningful only near the top of the result table; below tiebreakers might as well be ignored.

Usage of in particular these tiebreakers is not recommended: SOSOS, SODOS, ROS (CUSS), IROS.

Miscellaneous

  • The tournament system and all its details are specified and announced before the start of the tournament.
  • Pairing the same players twice must be avoided by all means. In a multi-stage tournament, repeated pairings must be delayed as long as possible or minimized in their frequency.
  • Each player's colour balance shall approach 50%. If two players meet again, then they get inverse colours.
  • For players starting above the top bar, the pairing is not biased by geography. Pairing by rating in early rounds may be applied only in multi-stage tournaments.
  • A pairing program has to be approved by the EGF Rules Commission.
  • By default, no handicaps are used. If handicaps are used for 15 kyu or below, then by default they use the rank difference minus 2.

Appendix

  • On 2007-05-11, the pairing programs approved by the EGF Rules Commission are: MacMahon, Gotha, GoDraw, GoMMtour.