Burstein system

The Burstein system is a Swiss pairing method. In a Swiss tournament, not everyone plays everyone else: new pairings are produced after each round, generally matching participants with similar scores while respecting additional constraints.

Burstein's distinctive idea is to compare the opposition each player has faced so far. After initial seeding rounds, meaning early rounds used to give the system a base before its distinctive method takes over, it builds an index from two measures. Buchholz adds the current scores of the opponents faced. Sonneborn-Berger weights each opponent's score according to the result scored against that opponent. Within the same scoregroup, the system tries to equalise opposition by matching high-index players with low-index players when the other rules allow it.

The index is used to make pairings, not to replace the players' actual tournament scores. Constraints such as avoiding repeat opponents and managing colours still matter. Colour difference measures the number of games played with White minus the number played with Black and helps determine colour preference.