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The Buchholz score is a tiebreak criterion for Swiss-system tournaments. In such a tournament each player meets only some of the participants, and everyone has different opponents. Buchholz shows how strong a player's opponents were.
The Swiss system in a nutshell
The tournament has several rounds. In each round opponents are paired among players with the same or similar number of points. That way, within 7–9 rounds, winners emerge even from hundreds of participants.
How to calculate it
The Buchholz score equals the sum of the points of all the player's opponents at the end of the tournament. The more points your opponents scored, the tougher your path through the tournament — and the higher you finish when points are equal.
Example
A five-round tournament. Ivan and Maria have 4 points each.
| Round | Ivan's opponent (points) | Maria's opponent (points) |
|---|---|---|
| 1 | 2 | 1 |
| 2 | 3 | 2½ |
| 3 | 3½ | 2 |
| 4 | 2½ | 3 |
| 5 | 4 | 3½ |
| Buchholz | 15 | 12 |
Ivan played stronger opponents, so with equal points he finishes higher.
Cut Buchholz
Sometimes the result of the weakest opponent (or of the weakest and the strongest) is left out of the sum. This reduces the effect of a lucky draw in the first round. Which variant is used is stated in the tournament regulations.
How it differs from Sonneborn–Berger
The Sonneborn–Berger score only counts the opponents you beat or drew with. Buchholz counts all opponents, whatever the result. That is why Buchholz suits Swiss tournaments and Sonneborn–Berger suits round-robins.