In the Swiss system the first round works like this: the top half of the starting list plays the bottom half. With a hundred players #1 plays #51, #2 plays #52. With a wide spread of ratings that is a hundred almost decided games. The strongest players meet only by the middle of the tournament, and there may not be enough rounds to find a winner.
Acceleration solves two problems. First, pairings are more even from round one, which makes them more interesting. Second, for title tournaments: players chasing a norm need strong opponents, and acceleration gives them sooner. That is exactly the goal FIDE names in the preface to the rules for accelerated systems.
Since 1 February 2026 FIDE approves one acceleration method - the Baku method (section C.04.7). Its essence is virtual points given to the stronger half of the field:
The size of group A is half the players, rounded up to an even number. With 100 players - 50, with 161 - 82 (the example from the FIDE rules). The method works only with the scoring "a win is worth two draws, a loss is zero".
The first half of the tournament is accelerated, rounded up. In the first half of the accelerated rounds group A gets a virtual point, in the second half - half a point.
| Tournament | Accelerated rounds | Virtual point | Virtual half point |
|---|---|---|---|
| 5 rounds | 1-3 | rounds 1-2: +1 | round 3: +0.5 |
| 7 rounds | 1-4 | rounds 1-2: +1 | rounds 3-4: +0.5 |
| 9 rounds | 1-5 | rounds 1-3: +1 | rounds 4-5: +0.5 |
| 11 rounds | 1-6 | rounds 1-3: +1 | rounds 4-6: +0.5 |
The example from the FIDE rules is nine rounds: five accelerated, group A gets an extra point in rounds 1-3 and half a point in rounds 4-5, and from round six pairing is normal.
Take 100 players with notional ratings from 2400 for #1 down to 1410 for #100 - exactly ten points lower with each number. Group A is numbers 1-50, group B is 51-100.
| Normal pairing | Accelerated pairing | |
|---|---|---|
| Board 1 | #1 (2400) - #51 (1900), gap 500 | #1 (2400) - #26 (2150), gap 250 |
| Board 25 | #25 (2160) - #75 (1660), gap 500 | #25 (2160) - #50 (1910), gap 250 |
| Board 26 | #26 (2150) - #76 (1650), gap 500 | #51 (1900) - #76 (1650), gap 250 |
| Board 50 | #50 (1910) - #100 (1410), gap 500 | #75 (1660) - #100 (1410), gap 250 |
Without acceleration the gap on every board is 500 points. With acceleration group A plays within itself, group B within itself, and the gap is halved. The weakest players benefit too: instead of near-hopeless games against the strongest, they get equal opponents.
If you do need acceleration - announce the method in the regulations before the tournament: that is a FIDE requirement (C.04.2, point 1.1), and the chief arbiter must state it in the tournament report (point 1.3).
In the Vibe Chess app Swiss pairings are made by an engine following the Dutch system. There is currently no acceleration in an individual tournament: all rounds follow the normal rules. For amateur meetups that is enough - the spread of strength is smaller there, and players can be split by level with groups within the tournament.
How pairing works in the app - online chess tournament pairing, about the engine itself - the bbpPairings engine.
A way of pairing a Swiss tournament in which the strongest players meet earlier: in the first rounds they get virtual points and are paired with each other.
Since 1 February 2026 the FIDE rules describe one method - the Baku method. Other methods may be used only with permission and with rules published in advance.
Group A gets a point per round in the first half of the accelerated rounds and half a point in the second. With 9 rounds - a point in rounds 1-3 and half a point in rounds 4-5.
No. They are only for pairing. Places in the tournament are decided by real points.
At small tournaments, with a small spread of strength and at junior and beginners' tournaments. There the ordinary Swiss system copes on its own.
Not at the moment: rounds of an individual Swiss tournament follow the normal Dutch system rules. If your tournament needs acceleration, write to the developers.
The Vibe Chess app is built for an evening over the board, not for online play: it keeps the sign-up list, the pairings and the table while you deal with people and the venue. All of it free.
The bot is constantly improved based on real tournaments. If you need a feature that isn't there yet, message the developers right inside the bot with the /support command. Many features appeared exactly because organizers asked for them, and useful ideas get added quickly.
More about pairings: colour in the first round, how many rounds in a Swiss system, manual pairing changes and a pairing error.
At the board since childhood: hazy about his rating, precise about every rook he has blundered. Counts an evening as a good one if the opponent stayed to talk afterwards instead of rushing off to check with an engine. Message →
