White 185 vs Black 315
White starts from setup 185 (NRNBBKRQ), Black from setup 315 (NQRKBRNB). In the encyclopedia since 2026-10-03: 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. 185, Black by position No. 315, 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 #185 N R N B B 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 185 gives White +0.27 (Morozov Balance Index, 400M nodes).
Black: setup #315 N Q R K B R N B
King on the d-file, rooks on c, f, queen on the b-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 315 gives White +0.29 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B, 3.2B nodes) the evaluation is exactly 0.00 each time, reaching search depth 59.
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 agreed early: from 100 thousand to 128 million nodes the evaluation never left ±15 cp.
For comparison, in symmetric play setup 185 gives White +0.27 and setup 315 gives White +0.29: 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 e3, and 2 first moves are within 10 cp of it.
Along the engine's main line (30 moves) the largest swing was 45 cp (around move 7), ending at +10 cp — the position stays playable for both sides.
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 | 12 | +15 | 1. c4 c6 2. h4 f5 3. g4 g6 4. gxf5 gxf5 |
| S1 | 500 000 | 19 | 0 | 1. d4 g6 2. Nab3 f5 3. g4 Bf7 4. Nd3 c6 |
| S2 | 2 000 000 | 23 | +6 | 1. d4 g6 2. Nab3 f5 3. g4 Nf6 4. gxf5 gxf5 |
| S3 | 8 000 000 | 26 | -7 | 1. g4 g6 2. e3 Nb6 3. Bf3 d5 4. d4 Bb5+ |
| S4 | 32 000 000 | 32 | +3 | 1. g4 g6 2. e3 f5 3. gxf5 gxf5 4. d4 c6 |
| S5 | 128 000 000 | 40 | +4 | 1. g4 g6 2. e3 f5 3. gxf5 gxf5 4. d4 O-O-O |
| S6 | 400 000 000 | 48 | 0 | 1. g4 g6 2. e3 f5 3. gxf5 gxf5 4. Bf3 c6 |
| S7 | 800 000 000 | 53 | 0 | 1. g4 g6 2. e3 f5 3. gxf5 gxf5 4. Bf3 c6 |
| S8 | 1 600 000 000 | 54 | 0 | 1. g4 g6 2. e3 f5 3. Nab3 c5 4. d3 fxg4 |
| S9 | 3 200 000 000 | 59 | 0 | 1. g4 g6 2. e3 f5 3. Nab3 c6 4. d4 Nf6 |
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: +8
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 -25, Black +7, difference -32. 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 | 0 | 41 | 1. e3 c5 2. g4 Nb6 3. Nab3 d5 4. d3 g6 5. Na5 Bd7 |
| 2 | 0 | 40 | 1. g4 c5 2. e3 Nb6 3. Nab3 d5 4. d3 g6 5. Na5 Bd7 |
| 3 | -15 | 40 | 1. d4 d6 2. g4 c5 3. dxc5 dxc5 4. e3 Bc6 5. Bf3 Nf6 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 45 cp, mean 19.6 cp, final +10 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | g4 | -20 | g6 | +2 |
| 2 | e3 | +13 | f5 | +12 |
| 3 | gxf5 | +23 | c6 | +21 |
| 4 | fxg6 | +20 | Bxg6 | +30 |
| 5 | h4 | +29 | O-O-O | +29 |
| 6 | d3 | +30 | Qd6 | +30 |
| 7 | Nab3 | +45 | Nc7 | +36 |
| 8 | h5 | +39 | Bf7 | +26 |
| 9 | Bf3 | +39 | Nh6 | +37 |
| 10 | Ne2 | +39 | Qf6 | +35 |
| 11 | Be4 | +30 | e5 | +29 |
| 12 | f4 | +33 | Qd6 | +28 |
| 13 | Bd2 | +33 | a5 | +26 |
| 14 | Nxa5 | +25 | Bxa2 | +25 |
| 15 | O-O-O | +23 | exf4 | +20 |
| 16 | Nxf4 | +17 | Nb5 | +27 |
| 17 | Nc4 | +26 | Qc5 | +29 |
| 18 | b3 | +20 | Rxf4 | +21 |
| 19 | d4 | +22 | Qe7 | +22 |
| 20 | Qh2 | +13 | Qxe4 | +18 |
| 21 | Qxf4 | +10 | Qxf4 | +9 |
| 22 | exf4 | +5 | Nxd4 | 0 |
| 23 | Ba5 | 0 | d5 | 0 |
| 24 | Ne5 | +11 | Ne2+ | +11 |
| 25 | Kd2 | +23 | Nxg1 | +23 |
| 26 | Bxd8 | +20 | Nh3 | +5 |
| 27 | Bb6 | +5 | Nxf4 | 0 |
| 28 | Nd3 | 0 | Nxd3 | 0 |
| 29 | Kxd3 | 0 | Ng4 | 0 |
| 30 | Rg1 | +1 | Ne5+ | +10 |
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 40.4 moves.
Sample game 1 (0-1)
1. g4 g6 2. b4 c6 3. Nab3 f5 4. e3 Nb6 5. gxf5 gxf5 6. d3 Qc7 7. c4 O-O-O 8. Ne2 Bf7 9. c5 Nd5 10. b5 Ngf6 11. Bd2 Ng4 12. h3 Ne5 13. Bc2 cxb5 14. Ba5 b6 15. cxb6 axb6 16. Bd2 Qb7 17. Nbd4 Nc7 18. Qxb7+ Kxb7 19. Nc3 Ne6 20. Ncxb5 Nxd4 21. Nxd4 Bxa2 22. Rb5 Ra8 23. Rg5 Rfc8 24. Rxf5 Nc6 25. Nxc6 dxc6 26. Rb4 Be6 27. d4 Bxf5 28. Bxf5 Rd8 29. Bc3 h6 30. Be4 Bf6 31. f4 Ra3 32. Rc4 Rc8 33. Ke2 Ra2+ 34. Kd3 e6 35. Bf3 Be7 36. Be1 b5 37. Rc1 Bd6 38. Rc2 Rxc2 39. Kxc2 Kb6 40. Bg4 Re8 41. Bc3 c5 42. dxc5+ Kxc5 43. Bh5 Rg8 44. Bg4 Rg6 45. Kd3 b4 46. Bd4+ Kb5 47. f5 exf5 48. Bxf5 Rg1 49. Bd7+ Ka5 50. Kc4 Bf8 51. e4 Rc1+ 52. Kd5 b3 53. Bf5 Kb4 54. Bb2 Rd1+ 55. Kc6 Rd2 56. Bh8 Rf2 57. h4 h5 58. Bf6 Rf4 59. Kc7 Bc5 60. Kd7 Bf2 61. Be7+ Kc3 62. Ba3 Bxh4 63. Bg6 Bg3 64. Be7 Rf1 65. e5 Bxe5 66. Bxh5 b2 67. Bg6 Rd1+ 68. Ke6 Rd3 69. Kxe5 b1=Q 70. Bf6 Kc4 71. Bf7+ Kc5 72. Be7+ Kc6 73. Be8+ Kc7 74. Bg6
Sample game 2 (1/2-1/2)
1. d4 g6 2. Nab3 c6 3. e4 f5 4. e5 d6 5. f4 c5 6. c3 Nh6 7. O-O Bc6 8. h3 O-O 9. Qh2 Nb6 10. Nd2 Nd5 11. Qg3 cxd4 12. cxd4 Nf7 13. Bb3 a5 14. Ne2 b5 15. Nc3 Qb7 16. a3 Nc7 17. Bf2 Bg7 18. Rfe1 e6 19. Nf3 Rfd8 20. Rbc1 b4 21. axb4 axb4 22. Na4 Nd5 23. Ra1 Bh6 24. Ng5 Nxg5 25. fxg5 Bf8 26. Qf3 Nc7 27. Qe3 dxe5 28. Qxe5 Bxg2 29. Nc5 Bxc5 30. dxc5 Bh1 31. Bxe6+ Nxe6 32. Qxe6+ Kf8 33. Qf6+ Kg8 34. Qe6+ Kf8 35. Qf6+ Kg8
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 185 / 315 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): nqrkbrnb/pppppppp/8/8/8/8/PPPPPPPP/NRNBBKRQ w BGcf - 0 1
Mirror twin: White 777 vs Black 353 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 41.