Appendix D: The FIDE Dubov System (FDS)
The following description is taken from the FIDE handbook.
C.04.3. The DUBOV Swiss Pairing System (Based on Rating)
Approved by the 1997 General Assembly.
Preface:
The DUBOV Swiss Pairing System is designed to maximise the fair treatment of the players. This
means that a player having a higher rating performance than another player during a tournament
should have more points as well.
If the average rating of all players is nearly equal, like in a round-robin tournament, the goal is
reached. As a Swiss System is a more or less statistical system, this goal can only be reached
approximately.
The approach is the attempt to equalise the average rating of the opponents of all players of a score
group. Therefore the pairing of a round will pair players who have played low rated players before
with players having high ratings now.
1. Introductory definitions
"R" is the rating of a player
"ARO" is the average rating of a player’s opponents. ARO must be calculated after each round as
basis of the pairings.
The "due color of a player is white",
- if he has played more games with black than with white before
- if these numbers are equal and he has played black his previous game.
The "due color of a player is black",
- if he has played more games with white than with black before
- if these numbers are equal and he has played white his previous game.
2. Pairings limitations
2.1 Two players who have played each other shall not be paired again.
2.2 A player who has received a point without playing shall not receive a bye.
2.3 The difference of the number of black and the number of white games shall not be greater than 2
or less than -2.
2.4 A player shall not have the same color three times in a row.
2.5 Apart from the last round a player cannot be transferred to a higher score group two times
running and more than three times (if the tournament has less than 10 rounds) or four times (if the
tournament has more than 9 rounds) during one tournament.
2.6 A player shall not be transferred from the subgroup due to a color to the subgroup due to the
other color if this would violate the limitations 2.3 or 2.4.
3. Color allocation.
When pairing two players the color allocation shall take into account with descending priority:
- giving both players their due color
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