The Swiss system in chess is a pairing method in which, in every round, each player faces an opponent on the same number of points as themselves, without ever meeting the same opponent twice. The number of rounds is fixed in advance, nobody is eliminated, and ties are broken by criteria such as the Buchholz.
The Swiss system is the format of almost every open: it lets dozens, even hundreds, of players compete over a limited number of rounds while still producing a winner. FIDE has set out its rules in its Handbook; the current version of its pairing system, known as the Dutch system, has applied since 1 February 2026, and its tiebreak rules since 1 March 2026.
Swiss round: a common expression for a round of a Swiss-system tournament, or for the tournament itself. The name comes from its origin: the system was first used in a chess tournament in Zurich, in the late 19th century.
The principles of the Swiss system in chess
- Pairing by score. Before each round, players are placed in score groups (everyone on 2 points, everyone on 1.5 points…). As far as possible, players are paired within each group.
- No repeat pairings. This is the only absolute criterion of the FIDE system: two players never meet more than once in the same tournament.
- Colour alternation. The aim is to give everyone as many games with White as with Black and to alternate colours. Among its quality criteria, the Dutch system limits colour differences greater than two and runs of three games in a row with the same colour.
- Floaters. When a score group has an odd number of players, or when certain pairings are impossible, a player “floats” to the neighbouring group and meets an opponent half a point or a point away.
- Bye. If the number of players is odd, the last unpaired player receives a bye. Under the FIDE basic rules, this pairing-allocated bye earns as many points as a win, unless the tournament regulations provide otherwise. Some regulations also allow a bye to be requested in advance, generally worth half a point.
In the first round, with no results yet, players are ranked by Elo rating and the list is split in two: the top player of the upper half meets the top player of the lower half, the second meets the second, and so on. The same principle then applies within each score group.
How many rounds are needed?
For a single player to finish with the maximum score, you need roughly as many rounds as the base-2 logarithm of the number of players: 3 rounds for 8 players, 4 for 16, 7 for 128. Opens often play more, because the aim is also to rank all the participants properly: nine rounds for the big festivals, eleven for the FIDE Grand Swiss or the European Individual Championship.
A worked example: an 8-player open over 3 rounds
Eight players, ranked from A (the strongest) to H. For simplicity, colours are ignored here, although they sometimes alter real pairings.
| Board | Pairing | Result |
|---|---|---|
| 1 | A – E | 1-0 |
| 2 | B – F | 1-0 |
| 3 | C – G | 1-0 |
| 4 | D – H | 0-1 (upset) |
After round 1, the 1-point group contains A, B, C and H; the 0-point group, D, E, F and G. Within each group, the list is split in two again.
| Group | Pairing | Result |
|---|---|---|
| 1 point | A – C | 1-0 |
| 1 point | B – H | ½-½ |
| 0 points | D – F | 1-0 |
| 0 points | E – G | ½-½ |
Before round 3, A is alone in the lead with 2 points. He “floats” to the 1.5-point group (B and H) and meets B, whom he has not yet played. H, left on his own, drops to the 1-point group and meets C (he has already played D). D in turn drops to the 0.5-point group and meets E; that leaves G against F. No pair has met before.
| Pairing | Result | Player | Points | Buchholz |
|---|---|---|---|---|
| A – B | 1-0 | A | 3 | 4 |
| H – C | 1-0 | H | 2.5 | 4.5 |
| D – E | ½-½ | B | 1.5 | 5.5 |
| G – F | 1-0 | D | 1.5 | 3.5 |
| G | 1.5 | 2 | ||
| C, E | 1 | – | ||
| F | 0 | – |
B, D and G all finish on 1.5 points. The Buchholz separates them: B's opponents (F, H and A) scored 0 + 2.5 + 3 = 5.5 points; D's (H, F and E) 2.5 + 0 + 1 = 3.5; G's (C, E and F) 1 + 1 + 0 = 2. B is therefore ranked third, D fourth and G fifth: B faced the strongest players in the tournament.
Tiebreaks explained
Tiebreaks are only used to rank players who are level on points. The tournament regulations must announce in advance which are used and in what order; failing that, FIDE provides for the chief arbiter to complete the list. The following definitions are those of the FIDE tiebreak regulations in force since 1 March 2026.
| Tiebreak | Principle | When it is used |
|---|---|---|
| Buchholz | Sum of the opponents' final scores | Swiss system |
| Buchholz Cut-1 (truncated) | Buchholz minus the score of the weakest opponent | Swiss system, to soften the effect of an opponent who forfeited or was very weak |
| Sonneborn-Berger | For each game, the opponent's final score multiplied by the points scored against them | Mainly round robins, sometimes in Swiss events |
| Direct encounter | Result of the games between the tied players | All formats, when the tied players have met |
| Number of wins | Number of rounds won (or of games won on the board, depending on the variant) | All formats |
| Average rating of opponents | Rounded average rating of the opponents met over the board | Swiss system |
| Performance rating | Average rating of opponents plus a difference derived from the percentage score, according to the FIDE table | Swiss system |
| Koya system | Points scored against players who made at least 50% | Round robins |
Buchholz variants are not allowed in a round-robin tournament, where they make no sense since everyone has the same opponents. For unplayed rounds (byes, forfeits), FIDE provides a specific method of calculation, using a “virtual” opponent, so as neither to penalise nor to favour the player who sat out. In France, open regulations often refer for this calculation to the method programmed in the Papi software.
Sonneborn-Berger: an example
Let us take B in the example above. He beat F (0 points at the end), drew with H (2.5 points) and lost to A. His Sonneborn-Berger is 0 × 1 + 2.5 × ½ + 3 × 0 = 1.25. This tiebreak rewards points taken against players who finished the tournament well.
Swiss system or round robin?
In a round-robin tournament, every player meets all the others: this is the format of elite closed tournaments, such as the Masters group at Tata Steel Chess (14 players, 13 rounds). The order of the games follows tables published by FIDE, the Berger tables. This format is fairer, since everyone has the same schedule, but it requires as many rounds as there are players minus one: impossible with 200 participants. The Swiss system is the compromise that makes big opens possible.
Pairing software
Nobody pairs an open by hand any more. In France, the arbiter generally uses Papi, the FFE's software, which also produces the results file sent in for approval. Swiss-Manager, approved by FIDE, is very widespread in Europe; it publishes pairings and standings on the chess-results website, where players follow their tournaments live. The FFE's national arbitration directorate (Direction nationale de l'arbitrage) also lists other tools, such as Sharly Chess or ChessEvent. The choice of software and the setting up of a tournament are covered on the page about organising a chess tournament.
Swiss pairings also presuppose precise regulations on the time control, announced in advance (see time controls in chess), and an arbiter to rule on special cases, such as forfeits or byes requested late (see the arbiter and tournament rules). To play a Swiss-system open near you, the Le Palais des Échecs directory lists clubs that run Swiss-system opens all over France.
Frequently asked questions
What is a Swiss round?
It is a round of a Swiss-system tournament: each player faces an opponent on the same number of points as themselves whom they have not yet met. By extension, the expression refers to the whole tournament played under this system.
How is the Buchholz calculated?
You add up the final scores of all the opponents met. For example, a player whose opponents finished on 3, 2.5 and 0 points has a Buchholz of 5.5. The higher the Buchholz, the tougher the path. Buchholz Cut-1 removes the score of the weakest opponent.
Can you play the same opponent twice in a Swiss tournament?
No. In the FIDE pairing system this is an absolute criterion: two players never meet more than once in the same tournament.
What happens if there is an odd number of players?
The player left without an opponent receives a bye. Under the FIDE basic rules, they score as many points as for a win, unless the tournament regulations say otherwise. Under the same rules, a player can only receive one pairing-allocated bye in the tournament.