White 526 vs Black 591
White starts from setup 526 (RNQKNBBR), Black from setup 591 (QRNKRNBB). 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 #526 R N Q K N B B R
King on the d-file, rooks on a, h, queen on the c-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 526 gives White +0.34 (Morozov Balance Index, 400M nodes).
Black: setup #591 Q R N K R N B B
King on the d-file, rooks on b, e, queen on the a-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 591 gives White +0.54 (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 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 -26 and 0 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.
For comparison, in symmetric play setup 526 gives White +0.34 and setup 591 gives White +0.54: with both sides on the same rank the first move is worth something. In this pair Black's own setup absorbs that edge completely.
The engine's first choice for White is a4; the alternatives are slightly weaker but keep the game level.
Along the engine's main line (30 moves) the largest swing was 34 cp (around move 10), ending at 0 cp — the position stays playable for both sides.
Engine self-play agrees: 10 games, White won 1, drawn 6, Black won 3 (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 | 13 | -26 | 1. f3 f5 2. d4 b5 3. Nd3 g5 4. Qxg5 Ne6 |
| S1 | 500 000 | 18 | -3 | 1. f3 b5 2. d4 f5 3. Nd3 a5 4. Nd2 g5 |
| S2 | 2 000 000 | 22 | -5 | 1. d4 g6 2. f3 e5 3. Qd2 f5 4. e4 Nd6 |
| S3 | 8 000 000 | 27 | -4 | 1. f3 f5 2. d4 Nd6 3. a4 b6 4. Bf2 g5 |
| S4 | 32 000 000 | 31 | -17 | 1. d4 f5 2. f3 Nd6 3. Nd3 g5 4. g4 Ne6 |
| S5 | 128 000 000 | 38 | 0 | 1. d4 b5 2. f3 f5 3. Nd3 Nd6 4. a4 b4 |
| S6 | 400 000 000 | 47 | -4 | 1. d4 f5 2. Nd3 b6 3. f3 Ne6 4. h4 g6 |
| S7 | 800 000 000 | 49 | 0 | 1. a4 g6 2. e3 e5 3. h4 Nd6 4. Bh2 f5 |
| S8 | 1 600 000 000 | 55 | 0 | 1. a4 g6 2. e3 e5 3. h4 Nd6 4. Bh2 f5 |
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: -14
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 +31, Black +88, difference -57. A balanced pair needs White's setup to be weaker by about the price of the first move.
Extended self-play: 10 games, 1 White wins, 6 draws, 3 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 | +28 | 40 | 1. a4 e5 2. h4 f5 3. e3 Nd6 4. Be2 b6 5. Bh2 g5 |
| 2 | +2 | 39 | 1. d4 f5 2. f3 Nd6 3. c3 a5 4. Nd3 b5 5. Bf2 g5 |
| 3 | -11 | 39 | 1. c3 g6 2. d4 e5 3. f3 f5 4. Bf2 b5 5. e3 exd4 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 34 cp, mean 8.7 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | f3 | +1 | f5 | -13 |
| 2 | d4 | -24 | b5 | -19 |
| 3 | Nd3 | -15 | Nd6 | -11 |
| 4 | a4 | -13 | b4 | -14 |
| 5 | h4 | -13 | g6 | -14 |
| 6 | Nd2 | -9 | Ne6 | -10 |
| 7 | e3 | -19 | Rc8 | -21 |
| 8 | c4 | -26 | bxc3 | -25 |
| 9 | Qxc3 | -22 | a5 | -26 |
| 10 | Nb3 | -34 | Nb7 | -23 |
| 11 | Qd2 | -23 | c5 | -33 |
| 12 | dxc5 | -19 | Nexc5 | -17 |
| 13 | Nbxc5 | -17 | Nxc5 | -7 |
| 14 | e4 | -10 | Bb3+ | -2 |
| 15 | Ke1 | -4 | Nxd3+ | -4 |
| 16 | Bxd3 | -5 | O-O | -9 |
| 17 | h5 | -5 | Bg7 | -5 |
| 18 | Be3 | -6 | fxe4 | -1 |
| 19 | Bxe4 | 0 | d5 | 0 |
| 20 | Bd3 | 0 | Qb8 | 0 |
| 21 | Kf1 | 0 | e5 | 0 |
| 22 | hxg6 | 0 | e4 | 0 |
| 23 | Rxh7 | 0 | exd3 | 0 |
| 24 | Bh6 | 0 | Bd4 | 0 |
| 25 | Qe3 | 0 | Qe5 | 0 |
| 26 | Rg7+ | 0 | Qxg7 | 0 |
| 27 | Qe6+ | 0 | Kh8 | 0 |
| 28 | Bxg7+ | 0 | Kxg7 | 0 |
| 29 | Qd7+ | 0 | Kf6 | 0 |
| 30 | Qd6+ | 0 | Kf5 | 0 |
Engine self-play
10 games at 500 000 nodes per move: White won 1, drawn 6, Black won 3 — White scored 40.0%. Average length 56.8 moves.
Sample game 1 (1/2-1/2)
1. d4 b6 2. Nf3 Nd6 3. h4 g6 4. e3 c5 5. c3 cxd4 6. exd4 f5 7. Bh2 Bd5 8. Be2 Ne6 9. O-O b5 10. Re1 O-O 11. Nbd2 f4 12. Qc2 Nf5 13. h5 b4 14. hxg6 hxg6 15. c4 Qc6 16. Qb1 Bxf3 17. Bxf3 Qd6 18. Bd5 Bxd4 19. Re4 Kg7 20. Nf3 Qc5 21. Nxd4 Nfxd4 22. b3 Rf6 23. Qb2 g5 24. Rd1 Rh8 25. Rexd4 Nxd4 26. Rxd4 Kf8 27. Rd3 d6 28. g4 Rfh6 29. Bf3 Rxh2 30. Rd5 Qc8 31. Rf5+ Ke8 32. Qd2 R2h3 33. Qd5 e6 34. Qxd6 exf5 35. Bc6+ Kf7 36. Bd5+ Ke8 37. Bc6+ Kf7 38. Bd5+ Ke8
Sample game 2 (1/2-1/2)
1. a4 Nd6 2. f3 f5 3. d4 b6 4. e3 g5 5. Nc3 Ng6 6. Qd2 a6 7. Bf2 e5 8. Be2 O-O-O 9. b3 Kb8 10. O-O-O a5 11. Kb1 Bf7 12. Nd3 exd4 13. exd4 Qc6 14. Kb2 h6 15. g3 Bc4 16. Rhe1 Re6 17. Kb1 Ba6 18. f4 gxf4 19. Nxf4 Nxf4 20. Bxa6 Nd5 21. Nxd5 Qxd5 22. Rxe6 Qxe6 23. Qf4 Ne4 24. Be1 Bg7 25. Be2 Rf8 26. Bf3 d5 27. Qe3 Ka7 28. Qf4 Rf7 29. g4 Ng5 30. gxf5 Nxf3 31. Qxf3 Rxf5 32. Qd3 Rf4 33. Qc3 Rf7 34. Bg3 Qg4 35. Rd3 Kb7 36. Be5 Bf8 37. Qe1 Qg2 38. Rd2 Qf3 39. Rd3 Qg2 40. Rd2 Qf3
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 526 / 591 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): qrnkrnbb/pppppppp/8/8/8/8/PPPPPPPP/RNQKNBBR w AHbe - 0 1
Mirror twin (the same position mirrored): White 532 vs Black 272.