White 183 vs Black 597
White starts from setup 183 (NRBNKRQB), Black from setup 597 (RQBBNKRN). In the encyclopedia since 2026-10-21: neither side starts better.
|cp| ≤ 5 at 400M · 800M · 1.6B · 4B nodes, two independent engines agree
The two setups
White: setup #183 N R B N K R Q B
King on the e-file, rooks on b, f, queen on the g-file; one bishop starts in a corner; the knights start away from the centre. Castling follows the Chess960 rule: king and rook end on the classical squares. In ordinary symmetric play setup 183 gives White +0.17 (Morozov Balance Index, 400M nodes).
Black: setup #597 R Q B B N K R N
King on the f-file, rooks on a, g, queen on the b-file; no bishop starts in a corner; the knights start away from the centre. Castling follows the Chess960 rule: king and rook end on the classical squares. In ordinary symmetric play setup 597 gives White +0.13 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation never left ±4 centipawns of equality, reaching search depth 56.
Admission rule: |cp| ≤ 5 at four budgets up to 4 billion nodes, no one-sided drift along the ladder, and confirmation by two independent engines — Berserk and Lc0 — each below its own median on symmetric positions. The same corridor is required at every deeper budget (8 G, 16 G) at which the pair has been evaluated.
The shallow rungs wandered between -17 and +15 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.
For comparison, in symmetric play setup 183 gives White +0.17 and setup 597 gives White +0.13: with both sides on the same rank the first move is worth something. In this pair Black's own setup absorbs that edge completely.
White is not forced into a single path: the best first move is b3, and 3 first moves are within 10 cp of it.
Along the engine's main line (13 moves) the evaluation stayed within ±16 cp the whole way: the balance holds as the pieces come out, not only on move one.
Engine self-play agrees: 10 games, White won 0, drawn 8, Black won 2 (White scored 40.0%).
Verification ladder
Nine independent searches of the starting position, each with a larger node budget. Evaluation in centipawns from White's point of view.
| Stage | Nodes | Depth | Eval, cp | Main line |
|---|---|---|---|---|
| S0 | 100 000 | 14 | -17 | 1. c4 c6 2. g3 O-O 3. f4 Nf6 4. b4 d5 |
| S1 | 500 000 | 20 | +2 | 1. c4 c6 2. g3 Nf6 3. Nc3 O-O 4. Qg2 e6 |
| S2 | 2 000 000 | 23 | +15 | 1. c4 c6 2. Nc3 O-O 3. f4 d5 4. cxd5 cxd5 |
| S3 | 8 000 000 | 27 | +6 | 1. c4 c6 2. g3 Nf6 3. Ne3 O-O 4. f4 e6 |
| S4 | 32 000 000 | 35 | +5 | 1. c4 c6 2. g3 O-O 3. f4 d5 4. cxd5 cxd5 |
| S5 | 128 000 000 | 45 | 0 | 1. c4 c6 2. Nc2 d5 3. b3 Bb6 4. g3 Nf6 |
| S6 | 400 000 000 | 47 | -2 | 1. c4 c6 2. Nc2 O-O 3. f4 d5 4. Nde3 dxc4 |
| S7 | 800 000 000 | 49 | -4 | 1. c4 c6 2. Nc2 O-O 3. g3 b5 4. cxb5 Qxb5 |
| S8 | 1 600 000 000 | 56 | 0 | 1. c4 c6 2. Nc2 Nf6 3. g3 d5 4. b3 Bb6 |
Deep verification
The search ladder reaches 1.6 billion nodes; admission needs a 4-billion rung and two further engines on top of that. Beyond even that, every pair was re-checked at budgets up to ten times larger and in thousands of self-play games. This section shows what each check returned for this pair.
| Nodes | Eval, cp |
|---|---|
| 4 000 000 000 | 0 |
| 8 000 000 000 | not checked |
| 16 000 000 000 | not checked |
This pair stays within the ±5 cp corridor up to 4 000 000 000 nodes.
Independent engines, run on the same position:
- Berserk 14: 0
- Lc0 0.32.1: -7
Independent confirmations: 3 of 3. An engine counts as confirming when its reading of the pair is closer to equality than its own reading of a typical symmetric Chess960 position (+10 for Berserk, +18 for Lc0). Where only one engine confirms, the pair is balanced according to that engine alone, and this page says so.
Own weight of each setup, measured against the classical array: White +56, Black +49, difference +7. A balanced pair needs White's setup to be weaker by about the price of the first move.
Extended self-play: 10 games, 0 White wins, 8 draws, 2 Black wins, White scored 40.0%.
Best first moves
The 3 best first moves for White, searched together at 400 000 000 nodes.
| # | Eval, cp | Depth | Main line |
|---|---|---|---|
| 1 | -2 | 43 | 1. b3 c6 2. c4 Ng6 3. g3 O-O 4. Nc2 e6 5. f4 d5 |
| 2 | -2 | 43 | 1. b3 c6 |
| 3 | -7 | 43 | 1. c4 c6 2. g3 Ng6 3. f4 e5 4. f5 Ne7 5. g4 O-O |
Main-line play-out
13 moves, 5 000 000 nodes per half-move. Largest |evaluation| 16 cp, mean 1.8 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | c4 | +12 | c6 | +2 |
| 2 | Nc2 | +8 | d5 | +6 |
| 3 | b3 | 0 | Bb6 | 0 |
| 4 | g3 | +3 | Nf6 | +16 |
| 5 | Bb2 | 0 | dxc4 | 0 |
| 6 | bxc4 | 0 | O-O | 0 |
| 7 | Nde3 | 0 | Ng4 | 0 |
| 8 | f4 | 0 | Nxe3 | 0 |
| 9 | Nxe3 | 0 | Bh3 | 0 |
| 10 | Rf3 | 0 | Bg4 | 0 |
| 11 | Rf1 | 0 | Bh3 | 0 |
| 12 | Rf3 | 0 | Bg4 | 0 |
| 13 | Rf1 | 0 | Bh3 | 0 |
Engine self-play
10 games at 500 000 nodes per move: White won 0, drawn 8, Black won 2 — White scored 40.0%. Average length 43.5 moves.
Sample game 1 (1/2-1/2)
1. b3 Nf6 2. Bb2 c6 3. c4 d5 4. Ne3 O-O 5. g3 Ng6 6. Bxf6 exf6 7. cxd5 cxd5 8. Bxd5 f5 9. f4 Ne7 10. Nac2 Bb6 11. Bf3 Be6 12. d4 Qd6 13. O-O-O Rac8 14. Rd3 Nd5 15. Nxd5 Bxd5 16. Bxd5 Qxd5 17. Kb1 Rfe8 18. Re3 Red8 19. Rd3 Re8 20. Re3 Red8 21. Rd1 Qc6 22. Rc1 Rc7 23. Na3 Qxc1+ 24. Qxc1 Rxc1+ 25. Kxc1 Bxd4 26. Rd3 Kf8 27. Nb5 Rc8+ 28. Kd2 Bc5 29. Rd7 a6 30. Nc7 Bg1 31. Ke1 Bb6 32. Nd5 Ba5+ 33. Kf2 Rb8 34. Ne3 Bb6 35. Kf3 Ke8 36. Rd5 g6 37. Nc4 Ba7 38. b4 f6 39. b5 axb5 40. Rxb5 Kd7 41. Na5 Kc7 42. h3 h5 43. a4 Bb6 44. Nc4 Ba7 45. Ra5 Bb6
Sample game 2 (1/2-1/2)
1. f4 d5 2. b3 c6 3. c4 Bb6 4. c5 Bc7 5. g3 O-O 6. b4 b6 7. Nc2 Nf6 8. Bb2 Ng6 9. Bxf6 exf6 10. Nd4 Ne7 11. Nc3 Bh3 12. Rf3 bxc5 13. bxc5 Qc8 14. Kf2 Bf5 15. Nxf5 Nxf5 16. Rd3 Qa6 17. Qc1 Rab8 18. Rxb8 Rxb8 19. Nd1 g5 20. Ra3 Qc8 21. e3 gxf4 22. exf4 Rb4 23. Rxa7 Kg7 24. Qc3 Rc4 25. Qd3 Rd4 26. Qe2 Qb8 27. Rxc7 Qxc7 28. Qg4+ Kf8 29. Qxf5 Rxd2+ 30. Ke1 Qa5 31. Qc8+ Kg7 32. Qg4+ Kh8 33. Bf3 Rxa2+ 34. Kf1 Qxc5 35. Qc8+ Kg7 36. Qg4+ Kh8 37. Qc8+ Kg7 38. Qg4+
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 183 / 597 in the app's encyclopedia, then choose how to play.
- Local game — two players on one device, with a clock.
- With a mentor — a clearly labelled training bot with hints, at your level.
- Challenge a friend — an online game by link; both players get the same pair, colours swap on rematch.
Play this pair against the computer, right here Play a friend
FEN (Shredder, castling rights by rook files): rqbbnkrn/pppppppp/8/8/8/8/PPPPPPPP/NRBNKRQB w BFag - 0 1
Mirror twin: White 770 vs Black 266 — a different position (castling squares are fixed), not evaluated by the search.