🏫 NWChess Pairings
Run a tournament from an NWChess RosterTable.csv export, with a choice of pairing engine: best-effort Swiss, or strict FIDE (Dutch) System rules for FIDE-rated events.
1 Roster
An NWChess RosterTable.csv export. FIDE ratings ignored; seeded by max(NWSRS, USCF); withdrawn players excluded; multiple sections supported.
2 Rounds
ⓘ How pairing logic works
This guide explains score groups, natural opponents, floaters, color due, and illegal matchups. Ratings seed players and break ties; current score remains the main pairing priority.
Top-half players sit on the left and bottom-half players on the right. A changed opponent means the engine had to depart from a natural pairing to solve a restriction.
Pairing order
- Requested byes: players who requested the round sit out first and receive ½ point.
- Score groups: remaining players are grouped by current score, highest group first.
- Floaters: a score group that can't pair internally (odd, or its only members already played each other) sends its lowest-priority player down into the next group so everyone can be paired.
- Illegal matchups: the engine backtracks to avoid a previous opponent. In Swiss mode a rematch is used only as a last resort if no rematch-free arrangement is available; in FIDE mode a rematch is never used — pairing the round fails with an explanation instead.
- Full bye: if the eligible field is still odd, the player with the fewest prior full byes is preferred; ties go to the lower score, then lower rating.
Color due (W / WW / B / BB)
W/B means due White/Black for equalization; WW/BB marks the stronger consecutive-color issue. A balance of −1 means one more Black than White. Byes do not count as a color. FIDE mode allocates colour via FIDE's own priority order instead (grant both sides' preference if possible, else the stronger/more urgent one, else the higher-ranked player).
Family, siblings, teams, and other protected pairings
Use the Family / sibling groups card below to mark players who shouldn't meet — siblings, parent/child, spouses, or any other group. In Swiss mode it's a soft rule, avoided whenever an alternative pairing exists but relaxed if the round genuinely can't be paired evenly otherwise; in FIDE mode it's enforced exactly as strictly as an absolute criterion. Team/school/club exclusions beyond marked groups aren't collected, so review the generated boards and use “Fix a mistake in this round” if you need a manual swap for something the engine doesn't know about.
Pairings are deterministic for the same roster and entered results. Manual swaps change the displayed pairing but do not add a permanent exclusion rule for later rounds.
Bye requests
Check off any player asking for a half-point bye in an upcoming round — they'll sit out with 0.5 points instead of being paired when you next click "Pair next round" for that round.
Family / sibling groups
Mark players who shouldn't be paired against each other when it can be avoided — siblings, parent/child, spouses, etc. Swiss mode treats this the same way it treats rematches: avoided whenever an alternative pairing exists, but not a hard rule that could leave the round unpairable. FIDE mode enforces it strictly.
Player status
Mark a player withdrawn if they've dropped out of the event — they're skipped when pairing every future round and no longer offered for byes or family groups. This doesn't change any round already paired; enter their current board as a normal result (or use "Fix a mistake in this round" for it).
3 Standings
Tiebreaks: Buchholz (sum of opponents' scores) then Sonneborn-Berger. Byes score a full point.
🗺 Wall Chart
Each cell is the opponent's current standings number, color, and result — w/b for White/Black, +/−/= for win/loss/draw. Opponent numbers update as standings change.