Accelerated Pairings
Accelerated pairings add fictitious (imaginary) points to top-rated players for pairing purposes only, narrowing the field faster and reducing early-round blowouts.
Enable accelerated pairings in Setup → Rules for Pairing.
How It Works
Top players receive extra points for pairing calculations in early rounds. These points:
- Affect pairings only — they do not count in standings or ratings
- Expire after the specified rounds — pairings return to normal afterward
- Create more competitive early games — top players face each other sooner
FIDE Baku System
Used automatically when running in FIDE mode with acceleration enabled.
The number of accelerated rounds and the bonus values are computed from the total number of rounds:
- Accelerated rounds = first half of total rounds (rounded up). For a 9-round event this is 5.
- Full bonus phase = first half of the accelerated rounds (rounded up). For 5 accelerated rounds this is rounds 1-3.
- Half bonus phase = remaining accelerated rounds. For 5 accelerated rounds this is rounds 4-5.
| Players | Early accelerated rounds | Later accelerated rounds | After acceleration ends |
|---|---|---|---|
| Top half of field | +1 point | +0.5 points | No adjustment |
| Bottom half of field | No adjustment | No adjustment | No adjustment |
For example, in a 9-round event: top-half players receive +1 point in rounds 1-3 and +0.5 points in rounds 4-5.
For FIDE events, SwissSys exports the acceleration data to the bbpPairings engine via XXA lines in the TRF file.
USCF Mode
USCF acceleration can be used at any time. The acceleration setting in Rules for Pairing offers three choices — Off, On (single acceleration), and Doubled (double acceleration, USCF only; the FIDE Baku combo only exposes Off and On).
Single acceleration (“On”)
The field is split in half. Every player in the top half receives a fictitious full point (+1.0) for pairing purposes; the bottom half receives no adjustment. This is the classic USCF accelerated-pairing scheme.
| Player group | Fictitious points |
|---|---|
| Top half of field | +1 point |
| Bottom half of field | No adjustment |
Double acceleration (“Doubled”)
Double acceleration divides the field into four quarters and gives a graduated bonus, producing a smoother spread than single acceleration:
| Player group | Fictitious points |
|---|---|
| Top quarter | +3 points |
| Second quarter | +2 points |
| Third quarter | +1 point |
| Bottom quarter | 0 points |
SwissSys stores scores internally as integers equal to twice the real score (a win is 2, a draw is 1), so the
engine adds the doubled equivalents — +6, +4, +2, and +0 — which correspond to the real +3, +2, +1,
and +0 shown above. Single acceleration adds the doubled equivalent of one full point (+2 internally) to each
top-half player.
The quarter boundaries are computed from the players actually being paired — byes and withdrawn players are excluded — so the divisions reflect the live field rather than the original entry count.
Board Assignment with Acceleration
When using accelerated pairings, you can assign boards based on either:
- True score — players ordered by their actual score
- Adjusted score — players ordered by their fictitious (accelerated) score
Set this preference on the Pair Chart tab of the Format Options dialog.
Notes
- In-depth searches are not compatible with accelerated pairings in USCF mode.
- Once acceleration is set for a FIDE tournament, the value cannot be changed after the tournament begins.
Related Topics
- Rules for Pairing — Enable acceleration and configure bye rules
- bbpPairings Engine — FIDE engine details
- Format Options — Board assignment display settings