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Buchholz Tiebreak Explained

Plus Sonneborn-Berger and Cumulative — what each one actually measures, and which to use.

In a Swiss or round-robin tournament, it's common for two or more players to finish with the exact same score. Since you usually need a single ranking (for prizes, seeding, or just bragging rights), tournaments use a tiebreak system — a secondary number calculated from the games already played, used only to break ties, never to change anyone's actual score.

Buchholz: "how tough were your opponents?"

Buchholz is the most common tiebreak in Swiss events. It's simply the sum of the final scores of every opponent you played. The idea: if two players end on the same score, the one who faced tougher opposition (opponents who themselves scored more points) gets ranked higher.

A common variant, Buchholz Cut 1, drops the lowest-scoring opponent's result before adding the rest, which softens the effect of one unusually weak pairing (often from a bye or early forfeit).

Sonneborn-Berger: "how well did you do against strong opponents?"

Sonneborn-Berger looks at the same set of opponents but weighs them by the result of the individual game, not just the final score:

• For every opponent you beat, add their full final score.
• For every opponent you drew, add half their final score.
• For every opponent you lost to, add nothing.

Sonneborn-Berger rewards players for beating strong opponents specifically, rather than just being anywhere near them in the draw — it's the standard tiebreak for round-robin events.

Cumulative (Progressive) score: "how consistently did you score?"

Cumulative score ignores opponents entirely and instead adds up your running total after every round. A player who wins early and coasts scores higher than one who loses early and rallies to the same final total — because the early points get counted again in every later round's running total.

Cumulative is easy to explain to players on the spot ("whoever was ahead more often wins the tie") and is popular for scholastic events for that reason, but it says nothing about opponent strength.

Which one should you use?

There's no rule that says you must use only one — many organizers list Buchholz as primary and Sonneborn-Berger as a secondary tiebreak for further ties. Whatever you choose, decide before the event starts and publish it, so nobody feels the rules changed after the fact.