White 510 vs Black 955
White starts from setup 510 (RQNKNBBR), Black from setup 955 (RKRNBNQB). In the encyclopedia since 2026-10-03: neither side starts better.
|cp| ≤ 5 at 400M · 800M · 1.6B · 4B nodes, two independent engines agree
The two setups
White: setup #510 R Q N K N B B R
King on the d-file, rooks on a, h, queen on the b-file; no bishop starts in a corner; the knights start on central files. Castling follows the Chess960 rule: king and rook end on the classical squares. In ordinary symmetric play setup 510 gives White +0.35 (Morozov Balance Index, 400M nodes).
Black: setup #955 R K R N B N Q B
King on the b-file, rooks on a, c, queen on the g-file; one bishop starts in a corner; the knights start on central files. Castling follows the Chess960 rule: king and rook end on the classical squares. In ordinary symmetric play setup 955 gives White +0.17 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation never left ±1 centipawns of equality, reaching search depth 55.
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 shallow rungs wandered between -12 and +19 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.
For comparison, in symmetric play setup 510 gives White +0.35 and setup 955 gives White +0.17: 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 a4, and 3 first moves are within 10 cp of it.
Along the engine's main line (30 moves) the largest swing was 55 cp (around move 15), ending at 0 cp — the position stays playable for both sides.
Engine self-play agrees: 10 games, White won 0, drawn 10, Black won 0 (White scored 50.0%).
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 | 15 | +19 | 1. c3 a5 2. a4 d6 3. f3 Nd7 4. h4 g6 |
| S1 | 500 000 | 19 | +3 | 1. c3 a5 2. a4 g6 3. e4 f5 4. f4 fxe4 |
| S2 | 2 000 000 | 24 | -12 | 1. a4 a5 2. c3 g6 3. e4 f5 4. f3 d6 |
| S3 | 8 000 000 | 31 | 0 | 1. a4 a5 2. c3 g6 3. e4 f5 4. f3 fxe4 |
| S4 | 32 000 000 | 38 | 0 | 1. a4 a5 2. c3 g6 3. e4 f5 4. f3 d6 |
| S5 | 128 000 000 | 40 | +5 | 1. c3 a5 2. a4 g6 3. Qa2 Nde6 4. e4 f5 |
| S6 | 400 000 000 | 48 | 0 | 1. c3 a5 2. a4 g6 3. f3 f5 4. Bf2 d6 |
| S7 | 800 000 000 | 51 | 0 | 1. c3 a5 2. a4 g6 3. e4 f5 4. f3 d5 |
| S8 | 1 600 000 000 | 55 | -1 | 1. c3 a5 2. a4 g6 3. f3 f5 4. e4 d5 |
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 | not checked |
| 8 000 000 000 | not checked |
| 16 000 000 000 | not checked |
This pair held exactly 0.00 up to 1 600 000 000 nodes.
Independent engines, run on the same position:
- Berserk 14: 0
- Lc0 0.32.1: -4
Independent confirmations: 2 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 -34, Black +70, difference -104. 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, 10 draws, 0 Black wins, White scored 50.0%.
Best first moves
The 3 best first moves for White, searched together at 400 000 000 nodes.
| # | Eval, cp | Depth | Main line |
|---|---|---|---|
| 1 | -5 | 45 | 1. a4 a5 2. c3 g6 3. f3 f5 4. e4 d5 5. Bb5 Bxb5 |
| 2 | -11 | 44 | 1. f3 a5 2. a4 f5 3. c3 g6 4. e4 d6 5. Be3 c5 |
| 3 | -13 | 44 | 1. c3 a5 2. a4 g6 3. f3 f5 4. e4 d5 5. Bb5 Bxb5 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 55 cp, mean 22.3 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | a4 | -11 | a5 | +3 |
| 2 | c3 | +16 | g6 | +13 |
| 3 | f3 | +4 | f5 | +6 |
| 4 | Bf2 | 0 | d6 | 0 |
| 5 | e3 | +3 | Nd7 | -3 |
| 6 | Nc2 | 0 | g5 | -13 |
| 7 | Bb5 | -7 | g4 | -32 |
| 8 | f4 | -27 | h5 | -32 |
| 9 | Nd4 | -49 | e6 | -29 |
| 10 | O-O | -39 | Bf6 | -45 |
| 11 | e4 | -54 | fxe4 | -54 |
| 12 | Qxe4 | -51 | h4 | -50 |
| 13 | Qe3 | -45 | c5 | -48 |
| 14 | Nc2 | -49 | Nc6 | -39 |
| 15 | Na3 | -37 | Nb6 | -55 |
| 16 | f5 | -43 | Bd7 | -31 |
| 17 | fxe6 | -35 | Re8 | -30 |
| 18 | Qf4 | -41 | Rxe6 | -30 |
| 19 | Bxc5 | -22 | Nd5 | -12 |
| 20 | Qc4 | -17 | Qg5 | -22 |
| 21 | Nd3 | -14 | O-O-O | -26 |
| 22 | Ba7 | -27 | Rde8 | -21 |
| 23 | Rae1 | -20 | Rxe1 | -36 |
| 24 | Nxe1 | -18 | Re7 | -22 |
| 25 | Nd3 | -24 | g3 | -12 |
| 26 | h3 | -2 | Kd8 | 0 |
| 27 | Nf4 | 0 | Nxf4 | -13 |
| 28 | Bb6+ | -6 | Ke8 | 0 |
| 29 | Qxf4 | 0 | Qxf4 | 0 |
| 30 | Rxf4 | 0 | Bg5 | 0 |
Engine self-play
10 games at 500 000 nodes per move: White won 0, drawn 10, Black won 0 — White scored 50.0%. Average length 40.9 moves.
Sample game 1 (1/2-1/2)
1. f3 g6 2. Bf2 d6 3. a4 a5 4. c3 f5 5. e4 fxe4 6. fxe4 g5 7. Bb5 Nde6 8. Nf3 Nf4 9. O-O c6 10. Be2 c5 11. Be3 Bf6 12. Bxf4 gxf4 13. Bb5 Bxb5 14. axb5 Ng6 15. Qc2 c4 16. Ne2 Rc5 17. Qa4 e5 18. d4 cxd3 19. Nc1 Rc4 20. Qa2 d5 21. Nxd3 dxe4 22. Nd2 exd3 23. Qxc4 Qxc4 24. Nxc4 e4 25. Nb6 Be7 26. Nxa8 Bc5+ 27. Kh1 e3 28. b6 e2 29. Nc7 exf1=B 30. Rxf1 d2 31. Ne6 Be3 32. Ng5 Ne5 33. Ne4 Nd3 34. Ra1 Bxb6 35. Nxd2 Nf2+ 36. Kg1 Ne4+ 37. Kf1 Nxd2+ 38. Ke2 Nc4 39. b4 axb4 40. cxb4 Bc7 41. Rd1 h5 42. Rd4 Ne3 43. Kf3 Ng4 44. h3 Nf6 45. Rd1 h4 46. b5 Kc8 47. Rd2 Be5 48. Re2 Bc7 49. Rd2 Ne8 50. Kg4 Bd8 51. Kxf4 Bc7+ 52. Kf5 b6 53. Rc2 Kd7 54. Rd2+ Ke7 55. Re2+ Kd7 56. Rd2+ Nd6+ 57. Kf6
Sample game 2 (1/2-1/2)
1. c3 d6 2. e4 a5 3. a4 f5 4. exf5 g6 5. f4 Nc6 6. Be3 Bd7 7. Bd3 gxf5 8. Bxf5 e5 9. Bxd7 Nxd7 10. Qf5 Nf6 11. fxe5 Ng4 12. exd6 Nxe3+ 13. dxe3 Ne5 14. Ncd3 Nc4 15. dxc7+ Rxc7 16. Ke2 Ra6 17. Rf1 Rf6 18. Qh5 Rb6 19. Rf5 Nxb2 20. Qg5 Qxg5 21. Rxg5 Bxc3 22. Ra2 Nc4 23. Rc2 Rb3 24. Rg8+ Ka7 25. Rg4 Na3 26. Rc1 Nc4 27. Nf3 Nb2 28. Nd4 Nxd3 29. Nxb3 Nxc1+ 30. Nxc1 b5 31. axb5 Kb6 32. Kd3 Bf6 33. Ne2 Kxb5 34. Rf4 Bg7 35. Rf5+ Ka6 36. Nd4 Bxd4 37. exd4 a4 38. Rf2 Kb5 39. Rb2+ Kc6 40. Rc2+ Kd6
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 510 / 955 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): rkrnbnqb/pppppppp/8/8/8/8/PPPPPPPP/RQNKNBBR w AHac - 0 1
Mirror twin (the same position mirrored): White 548 vs Black 1.