EGF Tournament System Rules
The most frequently used tournament systems for a tournament or one of
its stages are:
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.
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.
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.
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
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.
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
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
Indivisible prizes like seeding places or flight tickets are issued by
even if otherwise equal players share place number, title, or divisible
Tiebreakers might be used for none, one, or several of these purposes:
Different tiebreakers might be used for different purposes. Pairing
programs should allow such.
ordering the players in the final result list
distributing otherwise indivisible prizes
ordering the players for making pairings
determining seeded players
If only one tiebreaker is used, then these tiebreakers are recommended:
More than one tiebreaker might be used in a relative order of priority.
Number of Board Wins.
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:
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
Playing more rounds.
Playing playoff rounds, possibly with short thinking times.
Having equal players.
Recommended Usage of Tiebreakers
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.
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.
Usage of in particular these tiebreakers is not recommended: SOSOS,
SODOS, ROS (CUSS), IROS.
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.
On 2007-05-11, the pairing programs approved by the EGF Rules Commission
are: MacMahon, Gotha, GoDraw, GoMMtour.