White 42 vs Black 528
White starts from setup 42 (NNQRBBKR), Black from setup 528 (BBRNKQNR). In the encyclopedia since 2026-10-21: 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. 42, Black by position No. 528, 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 #42 N N Q R B B K R
King on the g-file, rooks on d, h, queen on the c-file; no bishop starts in a corner; the knights start away from the centre. The king already stands on a castled square, so one of the castlings moves only the rook. In ordinary symmetric play setup 42 gives White +0.23 (Morozov Balance Index, 400M nodes).
Black: setup #528 B B R N K Q N R
King on the e-file, rooks on c, h, queen on the f-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 528 gives White +0.24 (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 57.
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 ±14 cp.
For comparison, in symmetric play setup 42 gives White +0.23 and setup 528 gives White +0.24: 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 d4; the alternatives are slightly weaker but keep the game level.
Along the engine's main line (30 moves) the largest swing was 36 cp (around move 8), 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 | +1 | 1. d4 e6 2. Nc3 c5 3. dxc5 Qxc5 4. e4 Qe7 |
| S1 | 500 000 | 20 | +1 | 1. d4 b6 2. c4 f5 3. b4 c5 4. bxc5 bxc5 |
| S2 | 2 000 000 | 24 | +14 | 1. d4 b6 2. c4 f5 3. c5 Qf7 4. Nb3 Nf6 |
| S3 | 8 000 000 | 28 | +13 | 1. d4 b6 2. c4 f5 3. c5 Qf7 4. Nb3 Nf6 |
| S4 | 32 000 000 | 35 | 0 | 1. d4 f5 2. b4 b6 3. Nb3 Qf7 4. f3 Nf6 |
| S5 | 128 000 000 | 41 | +9 | 1. d4 f5 2. b4 b6 3. Nb3 Qf7 4. c4 Nf6 |
| S6 | 400 000 000 | 46 | 0 | 1. d4 f5 2. b4 b6 3. Nb3 Qf7 4. c4 Nf6 |
| S7 | 800 000 000 | 51 | 0 | 1. d4 f5 2. b4 b6 3. Nb3 Qf7 4. c4 Nf6 |
| S8 | 1 600 000 000 | 57 | 0 | 1. d4 f5 2. b4 b6 3. Nb3 Qf7 4. f3 f4 |
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: +11
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 +76, Black +103, 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, 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 | -6 | 42 | 1. d4 f5 2. b4 b6 3. Nb3 Qf7 4. c4 Nf6 5. e3 Qg6 |
| 2 | -20 | 41 | 1. b4 e5 2. d4 exd4 3. Nb3 Ne6 4. Nxd4 c5 5. bxc5 Qxc5 |
| 3 | -27 | 41 | 1. e3 f5 2. d4 b6 3. Nb3 Qf7 4. f3 Nf6 5. Bg3 Nh5 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 36 cp, mean 6.4 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | d4 | +8 | f5 | 0 |
| 2 | b4 | +17 | b6 | +15 |
| 3 | Nb3 | +3 | Qf7 | +6 |
| 4 | c4 | +10 | Nf6 | -14 |
| 5 | f3 | -13 | Qg6 | -24 |
| 6 | Nc3 | -29 | O-O | -25 |
| 7 | Bf2 | -23 | Ne6 | -26 |
| 8 | h4 | -36 | c6 | -13 |
| 9 | c5 | 0 | f4 | 0 |
| 10 | e3 | 0 | fxe3 | 0 |
| 11 | Qxe3 | 0 | Nf4 | 0 |
| 12 | Nc1 | +10 | Bb7 | +22 |
| 13 | a4 | +18 | Ba6 | +22 |
| 14 | b5 | -9 | cxb5 | 0 |
| 15 | axb5 | 0 | Bb7 | 0 |
| 16 | Nd3 | 0 | N6h5 | +4 |
| 17 | Nxf4 | +4 | Nxf4 | +5 |
| 18 | h5 | +6 | Qf7 | +4 |
| 19 | Ne4 | +3 | h6 | +13 |
| 20 | Rh4 | 0 | e6 | 0 |
| 21 | Bd3 | 0 | Nxh5 | 0 |
| 22 | Bb1 | 0 | Nf4 | 0 |
| 23 | Re1 | 0 | Bd5 | 0 |
| 24 | Nc3 | 0 | Bb7 | 0 |
| 25 | Ne4 | 0 | Bd5 | 0 |
| 26 | Nc3 | 0 | Bc4 | 0 |
| 27 | Qe4 | 0 | Qf5 | 0 |
| 28 | Qe3 | 0 | Qg5 | 0 |
| 29 | Rg4 | 0 | Qh5 | 0 |
| 30 | Rh4 | 0 | Qf7 | 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 44.4 moves.
Sample game 1 (1/2-1/2)
1. b4 b6 2. d4 c5 3. bxc5 bxc5 4. dxc5 f5 5. Nb3 Nf6 6. e3 Qf7 7. f3 Qg6 8. N1d2 Nd5 9. Bf2 Ne6 10. h4 O-O 11. Re1 Bg3 12. Bxg3 Qxg3 13. Ba6 Rb8 14. Bc4 Qc7 15. Nf1 Nb4 16. a3 Nc6 17. Qd2 Ne5 18. Bxe6+ dxe6 19. Qc3 Bd5 20. Nfd2 Bxb3 21. cxb3 Rfd8 22. O-O Rd3 23. Qc2 Qa5 24. b4 Qxa3 25. f4 Nc6 26. Ra1 Qc3 27. Qxc3 Rxc3 28. Rfb1 Rxb4 29. Rxb4 Nxb4 30. Rxa7 Nd5 31. h5 h6 32. Nf3 Nxe3 33. Nh4 Rc1+ 34. Kf2 Ng4+ 35. Ke2 Rc2+ 36. Ke1 Rc1+ 37. Ke2 Rc2+ 38. Ke1 Rxc5 39. Ng6 Kf7 40. Rxe7+ Kf6
Sample game 2 (1/2-1/2)
1. d4 b6 2. c4 f5 3. c5 Nf6 4. Nb3 Qf7 5. Nc3 O-O 6. f3 Nc6 7. e3 Nb4 8. Nd2 Nbd5 9. Bf2 Nxc3 10. bxc3 Qh5 11. Bc4+ e6 12. O-O bxc5 13. dxc5 Bd5 14. Bd3 c6 15. h3 g5 16. c4 Bxf3 17. Nxf3 g4 18. Nd4 gxh3 19. g3 e5 20. Be2 Qg6 21. Nf3 Ne4 22. Nh4 Qg5 23. Kh2 f4 24. Rg1 f3 25. Nxf3 Qg4 26. Rdf1 Nxf2 27. Qe1 Ne4 28. Nd2 Qg6 29. Nxe4 Qxe4 30. Qd2 Kh8 31. Bd3 Qg4 32. Qe2 Qxe2+ 33. Bxe2 a5 34. Bg4 Ba7 35. Bxd7 Rxf1 36. Rxf1 Rc7 37. Be8 Bxc5 38. Rf5 Re7 39. Bxc6 Bxe3 40. Be4 Kg7 41. Kxh3 Bd4 42. Rg5+ Kf6 43. Rh5 Rc7 44. Kg4 Rxc4 45. Rh6+ Kf7 46. Rxh7+ Ke6 47. Rh6+ Kd7 48. Rh7+ Ke6 49. Rh6+ Kd7 50. Rh7+
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 42 / 528 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): bbrnkqnr/pppppppp/8/8/8/8/PPPPPPPP/NNQRBBKR w DHch - 0 1
Mirror twin: White 917 vs Black 527 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 196.