Tuesday, May 22, 2012

Tie break systems

I have just been chatting with the reknown South African FIDE arbiter and organiser Gunther van den Bergh who has written his own pairing program using the FIDE-approved Dutch System about tie-breaks.

He echoes what I have always said that tie-break systems are not an exact science. In my estimate they are about 90% accurate. At end of tournament many parents were at pains to understand the Berger system of the pairing program Swissperfect in the round-robin option.

He was the Chief Arbiter in the All Africa Games in Maputo last year and here is what he writes:

"Hi

Firstly, there is no perfect tiebreak system. All are flawed in some way.

If I have to use tie-breaks (for Individual Swiss tournaments). I use the following four systems (in the order listed with the first listed being the most important):

- Median Bucholz (a.k.a. Bucholz Cut).
This is the same as bucholz BUT deducting the highest and lowest opponent scores. This tries to correct for opponents who did not play all their games, etc.

- Median Bucholz 2
Same as above but deductin the two highest and two lowest opponent scores.

- Sonneborn Berger
Sum of the scores of the opponents you have beaten plus half the scores of the opponents you have drawn with.

Depending on the size of the tournament. If the tournament is large (with many players) then use the above 3 systems. If there are few players in the tournament, then just use normal Bucholz (that is, no deductions are made as in Median Bucholz).

For Round-Robin tournaments:
The following are the best systems just for Round-Robin tournaments. In order:
- Direct encounter (the results between the players with the same score).
- Sonneborn-Berger
- Koya (your results against players who scored 50% or more)
- Greatest number of wins

As mentioned, there is no perfect system - all systems are flawed. But, if you do decide to have tiebreaks, make sure that these (the tie-breaks to be used) are advertised (made known to the players) in advance (before the start of the tournament).

The best possible tiebreak for a round-robin is to have a play-off between the players tying for 1st place. Usually they play two rapid games and the winner is the one scoring 1.5 or two. If the scores are still tied, then they play two blitz games. If the scores are still tied they play one armageddon game (black declared the winner if the game is drawn).

Hope this helps.

Regards

Günther van den Bergh
Article by
John Mubaki

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