White 181 vs Black 589
White starts from setup 181 (NRBBNKRQ), Black from setup 589 (QRNBKRBN). 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 #181 N R B B N K R Q
King on the f-file, rooks on b, g, queen on the h-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 181 gives White +0.42 (Morozov Balance Index, 400M nodes).
Black: setup #589 Q R N B K R B N
King on the e-file, rooks on b, f, queen on the a-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 589 gives White +0.36 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation is exactly 0.00 each time, reaching search depth 58.
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 agreed early: from 100 thousand to 128 million nodes the evaluation never left ±11 cp.
For comparison, in symmetric play setup 181 gives White +0.42 and setup 589 gives White +0.36: 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 g4, and 2 first moves are within 10 cp of it.
Along the engine's main line (14 moves) the evaluation stayed within ±14 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 9, Black won 1 (White scored 45.0%).
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 | 0 | 1. g4 b5 2. Qxa8 Rxa8 3. b3 f6 4. c3 c6 |
| S1 | 500 000 | 17 | -3 | 1. Nb3 a5 2. a4 Nd6 3. d3 b6 4. c4 e5 |
| S2 | 2 000 000 | 25 | +11 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 a5 |
| S3 | 8 000 000 | 28 | -5 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 e5 |
| S4 | 32 000 000 | 36 | +11 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 a5 |
| S5 | 128 000 000 | 45 | 0 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 e5 |
| S6 | 400 000 000 | 52 | 0 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 Ng6 |
| S7 | 800 000 000 | 55 | 0 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 Ng6 |
| S8 | 1 600 000 000 | 58 | 0 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 Ng6 |
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: -6
- Lc0 0.32.1: -6
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 -16, Black +11, difference -27. 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, 9 draws, 1 Black wins, White scored 45.0%.
Best first moves
The 3 best first moves for White, searched together at 400 000 000 nodes.
| # | Eval, cp | Depth | Main line |
|---|---|---|---|
| 1 | +6 | 41 | 1. g4 f6 2. b3 b5 3. Qxa8 Rxa8 4. c3 a5 5. Nac2 a4 |
| 2 | -2 | 40 | 1. c3 b6 2. g3 f5 3. Bb3 e5 4. Nac2 Bf6 5. Qxa8 Rxa8 |
| 3 | -8 | 41 | 1. c3 b6 |
Main-line play-out
14 moves, 5 000 000 nodes per half-move. Largest |evaluation| 14 cp, mean 2.1 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | g4 | -5 | f6 | -5 |
| 2 | b3 | -14 | b5 | -7 |
| 3 | Qxa8 | 0 | Rxa8 | +3 |
| 4 | c3 | 0 | Ng6 | 0 |
| 5 | Nac2 | -3 | e5 | 0 |
| 6 | Ne3 | +8 | Nf4 | +8 |
| 7 | Bc2 | 0 | c6 | 0 |
| 8 | a4 | 0 | bxa4 | -5 |
| 9 | bxa4 | 0 | g6 | 0 |
| 10 | h4 | 0 | Ba2 | 0 |
| 11 | Ra1 | 0 | Be6 | 0 |
| 12 | Rb1 | 0 | Ba2 | 0 |
| 13 | Ra1 | 0 | Be6 | 0 |
| 14 | Rb1 | 0 | Ba2 | 0 |
Engine self-play
10 games at 500 000 nodes per move: White won 0, drawn 9, Black won 1 — White scored 45.0%. Average length 38.1 moves.
Sample game 1 (0-1)
1. d4 a5 2. Nb3 f5 3. g4 a4 4. Nd2 Nd6 5. gxf5 Nxf5 6. Nef3 Qa6 7. c3 Ng6 8. h4 Bd5 9. Ke1 Nfxh4 10. e4 Nxf3+ 11. Bxf3 Bg8 12. Qh5 e5 13. Be2 Qb6 14. Nf3 exd4 15. Nxd4 Bf6 16. Be3 Bxa2 17. Nb5 Qc6 18. Rd1 O-O 19. Rh1 h6 20. f3 Rbe8 21. Bxh6 Re5 22. Qg4 Rxb5 23. Bxb5 Qxb5 24. Qxg6 Qxb2 25. Qh7+ Kf7 26. Bd2 Qb6 27. Qh5+ g6 28. Qh7+ Ke8 29. Qxg6+ Bf7 30. Qh6 Rg8 31. Qe3 Qb5 32. Bc1 b6 33. Ba3 Bb3 34. Rd2 Qe5 35. Rdh2 Qg3+ 36. Ke2 Bc4+ 37. Kd1 Bb3+ 38. Ke2 Bc4+ 39. Kd1 Kd8 40. Kc2 Kc8 41. Kb1 Kb7 42. Rb2 d6 43. Rd1 Be5 44. Rb4 Bb3 45. Rxb3 axb3 46. Kb2 Rf8 47. Rf1 Ra8 48. Ra1 Qg2+ 49. Kxb3 Rf8 50. Bxd6 Rxf3 51. Qxf3 Qxf3 52. Bxe5 Qxe4 53. Bxc7 Kxc7 54. Kb2 Qe2+ 55. Kb3 Qd3 56. Ra2 Kc6 57. Kb2 Kd6 58. Kc1 Kc5 59. Ra7 Qxc3+ 60. Kd1 Qe3 61. Rc7+ Kb4 62. Rd7 Qf4 63. Ke1 Qg3+
Sample game 2 (1/2-1/2)
1. g3 f5 2. b3 e5 3. c4 Bf6 4. Nac2 Be6 5. O-O e4 6. Ba3 Ne7 7. e3 b5 8. cxb5 Rxb5 9. Nd3 Bd5 10. Nf4 Nhg6 11. Nxd5 Qxd5 12. Be2 Ra5 13. Rfd1 Ne5 14. Bb2 Nd3 15. Bc3 Rxa2 16. Bxd3 Bxc3 17. dxc3 exd3 18. Qxd5 Nxd5 19. Rxd3 Nf6 20. Nb4 Ra3 21. Nc2 Ra5 22. c4 Ne4 23. Rbd1 d6 24. Nd4 Kd7 25. b4 Ra2 26. f3 Nf2 27. R1d2 Nxd3 28. Rxa2 Ra8 29. b5 Ne5 30. Ra4 g6 31. Kf2 c5 32. bxc6+ Nxc6 33. Nxc6 Kxc6 34. Ra5 Kb6 35. Rb5+ Kc6 36. Ra5 Kb6 37. Rb5+ Kc7 38. Ra5
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 181 / 589 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): qrnbkrbn/pppppppp/8/8/8/8/PPPPPPPP/NRBBNKRQ w BGbf - 0 1
Mirror twin (the same position mirrored): White 778 vs Black 280.
Current place in the live balance rating: 145.