White 59 vs Black 42

The two setups

White: setup #59 N N R Q B K R B

King on the f-file, rooks on c, g, queen on the d-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 59 gives White +0.25 (Morozov Balance Index, 400M nodes).

Black: 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).

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 62.

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 ±12 cp.

For comparison, in symmetric play setup 59 gives White +0.25 and setup 42 gives White +0.23: 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 c4; the alternatives are slightly weaker but keep the game level.

Along the engine's main line (30 moves) the largest swing was 38 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 8, Black won 2 (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.

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.

This pair held exactly 0.00 up to 1 600 000 000 nodes.

Independent engines, run on the same position:

• Berserk 14: -7
• Lc0 0.32.1: +1

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 +38, Black +76, difference -38. 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, 8 draws, 2 Black wins, White scored 40.0%.

Best first moves

The 3 best first moves for White, searched together at 400 000 000 nodes.

Main-line play-out

30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 38 cp, mean 16.0 cp, final 0 cp.

Engine self-play

10 games at 500 000 nodes per move: White won 0, drawn 8, Black won 2 — White scored 40.0%. Average length 48.8 moves.

1. c4 Nb6 2. f4 c5 3. Bf2 e5 4. Bh4 exf4 5. Bxd8 Qxd8 6. O-O h5 7. Nc3 Nxc4 8. Rxf4 Nb6 9. g3 Nc6 10. e3 d5 11. Nb3 Be7 12. Qe2 h4 13. d4 cxd4 14. exd4 hxg3 15. hxg3 Bd6 16. Rh4 Rxh4 17. gxh4 Ne7 18. Na5 Qb8 19. Rf1 Bd7 20. Qf2 Be6 21. Ne2 Nf5 22. Bf3 Nh6 23. Nb3 Nc4 24. Nc5 Qc8 25. Rc1 Ng4 26. Bxg4 Bxg4 27. Nf4 b6 28. Ncd3 Bf5 29. Ne5 Be4 30. Qg3 Qf5 31. Qg5 Qxg5+ 32. hxg5 Nxe5 33. dxe5 Bxe5 34. Ne2 Bxb2 35. Rc7 d4 36. Kf2 a6 37. Rc8+ Kh7 38. Nf4 g6 39. Rd8 Bb1 40. a4 Bc2 41. Nd5 d3 42. Nb4 Bxa4 43. Nxd3 Ba3 44. Rb8 Bb5 45. Ke3 Bxd3 46. Kxd3 Bc5 47. Ra8 a5 48. Ke4 Kg7

1. c4 Nb6 2. c5 Nd5 3. g3 Nf6 4. d3 e5 5. Nb3 b6 6. O-O d5 7. Bd2 Be7 8. Nc3 O-O 9. Bg5 Qe6 10. d4 e4 11. f3 Bc6 12. e3 Rfe8 13. fxe4 Nxe4 14. Bxe7 Nxc3 15. Rxc3 Rxe7 16. Re1 Nd7 17. cxb6 cxb6 18. Nc1 Nf6 19. Nd3 Bb5 20. Ne5 Rc8 21. Rxc8+ Qxc8 22. Qb3 Ba6 23. Bxd5 Nxd5 24. Qxd5 Bb7 25. Qd6 Qe8 26. Ng4 h6 27. Nf2 Rd7 28. Qf4 Qe6 29. Qb8+ Kh7 30. e4 a5 31. a3 Re7 32. Rf1 Qd7 33. d5 f5 34. Nd1 b5 35. Qf4 Rxe4 36. Qxf5+ Qxf5 37. Rxf5 Kg6 38. Rf1 Bxd5 39. Nc3 Rd4 40. Ne2 Rd2 41. Nf4+ Kh7 42. Rf2 Rd4 43. Nxd5 Rxd5 44. Kf1 Rd3 45. Ke2

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 59 / 42 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): nnqrbbkr/pppppppp/8/8/8/8/PPPPPPPP/NNRQBKRB w CGdh - 0 1

Mirror twin (the same position mirrored): White 897 vs Black 917.