White 90 vs Black 573
White starts from setup 90 (NNRKBBRQ), Black from setup 573 (RNKBNRBQ). In the encyclopedia since 2026-10-09: neither side starts better.
|cp| ≤ 5 at 400M · 800M · 1.6B · 4B nodes, two independent engines agree
How to play with different setups
White sets up the pieces by position No. 90, Black by position No. 573, mirrored on their own side; the pawns stand as usual.
Moves as usual: White starts; everything else follows the Chess960 rules.
The two setups
White: setup #90 N N R K B B R Q
King on the d-file, rooks on c, 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 90 gives White +0.31 (Morozov Balance Index, 400M nodes).
Black: setup #573 R N K B N R B Q
King on the c-file, rooks on a, f, queen on the h-file; no bishop starts in a corner; the knights start on central files. The king already stands on a castled square, so one of the castlings moves only the rook. In ordinary symmetric play setup 573 gives White +0.33 (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 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 same corridor is required at every deeper budget (8 G, 16 G) at which the pair has been evaluated.
The shallow rungs wandered between -11 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 90 gives White +0.31 and setup 573 gives White +0.33: 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 c4, and 2 first moves are within 10 cp of it.
Along the engine's main line (30 moves) the largest swing was 33 cp (around move 4), ending at 0 cp — the position stays playable for both sides.
Engine self-play agrees: 10 games, White won 0, drawn 6, Black won 4 (White scored 30.0%).
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 | -11 | 1. g4 h5 2. g5 e5 3. O-O-O f5 4. d3 Bxa2 |
| S1 | 500 000 | 21 | +1 | 1. d3 f5 2. c4 e5 3. O-O-O h5 4. g3 Nc6 |
| S2 | 2 000 000 | 25 | +14 | 1. g4 h5 2. h3 e5 3. d3 Nc6 4. O-O-O hxg4 |
| S3 | 8 000 000 | 31 | +19 | 1. g4 h5 2. h3 g6 3. c4 f5 4. d3 e5 |
| S4 | 32 000 000 | 37 | 0 | 1. g4 Nc6 2. c4 g6 3. d3 Qxb2 4. Nc3 e5 |
| S5 | 128 000 000 | 40 | 0 | 1. c4 Nc6 2. d3 e5 3. g4 g6 4. b4 a6 |
| S6 | 400 000 000 | 50 | 0 | 1. g4 Nc6 2. d3 g6 3. c4 Qxb2 4. Nc3 e5 |
| S7 | 800 000 000 | 55 | 0 | 1. g4 Nc6 2. d3 g6 3. c4 Qxb2 4. Nc3 e5 |
| S8 | 1 600 000 000 | 54 | 0 | 1. g4 Nc6 2. d3 g6 3. c4 Qxb2 4. Nc3 e5 |
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: +1
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 +34, Black +88, difference -54. 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, 6 draws, 4 Black wins, White scored 30.0%.
Best first moves
The 3 best first moves for White, searched together at 400 000 000 nodes.
| # | Eval, cp | Depth | Main line |
|---|---|---|---|
| 1 | +13 | 41 | 1. c4 f5 2. d3 e5 3. g4 fxg4 4. b4 Bg5 5. Nd2 h5 |
| 2 | +8 | 40 | 1. d3 f5 2. c4 e5 3. g4 fxg4 4. b4 Bg5 5. Nd2 h5 |
| 3 | 0 | 40 | 1. g4 Nc6 2. c4 g6 3. d3 Qxb2 4. Nc3 e5 5. Nc2 Qb6 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 33 cp, mean 13.0 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | g4 | +13 | Nc6 | +6 |
| 2 | O-O-O | -1 | e5 | -18 |
| 3 | d3 | -17 | f5 | -24 |
| 4 | gxf5 | -16 | Bxa2 | -33 |
| 5 | c4 | -15 | Bxb1 | -21 |
| 6 | Kxb1 | -12 | Rxf5 | -21 |
| 7 | Nc2 | -27 | a5 | -26 |
| 8 | Bg2 | -24 | Ra6 | -18 |
| 9 | Be4 | -22 | Rh5 | -17 |
| 10 | e3 | -16 | Qf8 | -15 |
| 11 | Bc3 | -26 | g6 | -23 |
| 12 | f4 | -21 | exf4 | -17 |
| 13 | Bf3 | -16 | Rh4 | -29 |
| 14 | Be1 | -17 | Rh6 | -23 |
| 15 | Rf1 | -22 | g5 | -17 |
| 16 | exf4 | -12 | gxf4 | -33 |
| 17 | d4 | -9 | Qf5 | -8 |
| 18 | Be4 | -12 | Qh5 | -21 |
| 19 | Bd2 | -15 | Qxh2 | -14 |
| 20 | Bxf4 | -15 | Qxh1 | -11 |
| 21 | Rxh1 | -7 | Rxh1 | -5 |
| 22 | Rxh1 | -8 | a4 | -6 |
| 23 | Bf5 | -7 | Nf6 | -6 |
| 24 | Bxh7 | -5 | Nxh7 | 0 |
| 25 | Rxh7 | 0 | Na5 | 0 |
| 26 | Rh8 | 0 | Rg6 | -6 |
| 27 | c5 | -4 | Nc4 | -4 |
| 28 | Ka2 | 0 | Rg4 | 0 |
| 29 | Rf8 | 0 | b5 | 0 |
| 30 | Na3 | 0 | Nxa3 | 0 |
Engine self-play
10 games at 500 000 nodes per move: White won 0, drawn 6, Black won 4 — White scored 30.0%. Average length 53.8 moves.
Sample game 1 (1/2-1/2)
1. d3 f5 2. O-O-O g5 3. c4 e5 4. g3 Nc6 5. Nc3 Bf6 6. Kb1 O-O-O 7. Bg2 h5 8. f4 exf4 9. gxf4 gxf4 10. Rf1 h4 11. Nc2 h3 12. Bd5 Nd6 13. Rxf4 Bxd5 14. Qxd5 Qh6 15. Rf2 Rde8 16. Bd2 Qh5 17. c5 Bxc3 18. Bxc3 Nb5 19. Bg7 Rg8 20. Bf6 Rgf8 21. Qxf5 Qxf5 22. Rxf5 b6 23. Rdf1 bxc5 24. R1f2 Nbd4 25. Nxd4 Nxd4 26. Bxd4 Rxf5 27. Rxf5 cxd4 28. Rf2 Kb7 29. Kc1 Rg8 30. Rf3 Rg1+ 31. Kd2 Rb1 32. b3 Rb2+ 33. Kd1 Rxa2 34. Rxh3 Ra1+ 35. Kc2 Ra2+ 36. Kd1 d6 37. Rh8 Ra1+ 38. Kd2 Ra2+ 39. Kd1 Rb2 40. Rh4 c5
Sample game 2 (0-1)
1. g4 e5 2. d3 Nc6 3. c4 g6 4. b4 a6 5. Bg2 Bg5 6. Rc2 f5 7. gxf5 Bf6 8. Nc3 gxf5 9. Bd5 e4 10. Nb3 Nxb4 11. Bxb7+ Kxb7 12. Nxe4 fxe4 13. Bxb4 Nd6 14. Bxd6 cxd6 15. Qxe4+ Kb8 16. c5 Ka7 17. c6 Bxb3 18. axb3 Rfc8 19. Qe3+ Bd4 20. Qe7 Qd8 21. Qxd6 dxc6 22. Qxd8 Rxd8 23. Rxc6 Rac8 24. Rxc8 Rxc8 25. e3 Bf6 26. d4 Rc3 27. Kd2 Rxb3 28. Kc2 Rb4 29. Kc3 a5 30. f4 Ka6 31. Rg8 Kb7 32. Rg1 Ka7 33. Rg2 Ra4 34. Kb3 Ra1 35. Kc4 Re1 36. Kd3 Kb6 37. Rb2+ Ka7 38. Rb5 Bd8 39. f5 Ka6 40. Rd5 Bc7 41. Rc5 Bb6 42. Rc2 Bd8 43. Rg2 Bf6 44. Rg8 Kb7 45. Rg2 Ka7 46. h3 Kb6 47. Rg8 Kb7 48. Rg2 Ka6 49. Rg8 Ka7 50. Rf8 Bg5 51. Re8 Kb7 52. h4 Bxh4 53. Kc4 h5 54. Re6 Bd8 55. e4 Rc1+ 56. Kb3 Rb1+ 57. Kc2 Rf1 58. Rd6 Kc8 59. Rc6+ Kd7 60. Rh6 h4 61. Rh7+ Kc6 62. Kc3 Kb5 63. Rb7+ Bb6 64. d5 h3 65. Rh7 Rf3+ 66. Kc2 a4 67. e5 a3 68. e6 a2 69. e7 Re3 70. Rh6 a1=Q 71. e8=Q+ Rxe8 72. Rxb6+ Kxb6
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 90 / 573 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): rnkbnrbq/pppppppp/8/8/8/8/PPPPPPPP/NNRKBBRQ w CGaf - 0 1
Mirror twin: White 869 vs Black 488 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 397.