White 106 vs Black 499

The two setups

White: setup #106 Q N R N B B K R

King on the g-file, rooks on c, h, queen on the a-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 106 gives White +0.26 (Morozov Balance Index, 400M nodes).

Black: setup #499 B R Q N K N R B

King on the e-file, rooks on b, g, queen on the c-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 499 gives White +0.18 (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 -21 and +6 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 106 gives White +0.26 and setup 499 gives White +0.18: 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 evaluation stayed within ±28 cp the whole way: the balance holds as the pieces come out, not only on move one.

Engine self-play agrees: 10 games, White won 3, drawn 7, Black won 0 (White scored 65.0%).

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 stays within the ±5 cp corridor up to 4 000 000 000 nodes.

Independent engines, run on the same position:

• Berserk 14: +6
• 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 +27, Black +115, difference -88. A balanced pair needs White's setup to be weaker by about the price of the first move.

Extended self-play: 10 games, 3 White wins, 7 draws, 0 Black wins, White scored 65.0%.

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| 28 cp, mean 10.6 cp, final +9 cp.

Engine self-play

10 games at 500 000 nodes per move: White won 3, drawn 7, Black won 0 — White scored 65.0%. Average length 56.4 moves.

1. d4 d5 2. h4 g5 3. hxg5 Nde6 4. c3 Nxg5 5. Nd2 Qd7 6. g3 e5 7. dxe5 Bxe5 8. Bg2 O-O-O 9. Qb1 Kb8 10. Kf1 Ng6 11. Ne3 b6 12. Nf3 Nxf3 13. Bxf3 Rge8 14. Nf5 Bb7 15. Rd1 Bf6 16. Qc2 Re5 17. Bg4 Rde8 18. Rh5 Re4 19. Bf3 R4e5 20. Bg4 Re4 21. Bf3 R4e5

1. d4 g5 2. c3 b6 3. Nd2 d5 4. e3 Qd7 5. f3 e5 6. Qb1 Nde6 7. Bd3 Bb7 8. O-O h5 9. b4 Ng6 10. a4 Qxa4 11. b5 Qa3 12. Rc2 Ra8 13. Ra2 Qd6 14. Kh1 Qd7 15. Bg3 Qe7 16. Kg1 Bg7 17. Bxg6 fxg6 18. Qxg6+ Qf7 19. Qd3 exd4 20. cxd4 h4 21. Be5 Bxe5 22. dxe5 Nc5 23. Qd4 h3 24. Nf2 hxg2 25. Rfa1 Rf8 26. Ng4 Qg6 27. Nf6+ Kf7 28. f4 Ne6 29. Qc3 gxf4 30. Nf3 Qf5 31. exf4 Qxf4 32. Rf2 Ke7 33. Qa3+ Nc5 34. Rd1 Rh8 35. Rd4 Qf5 36. Qa1 Qh3 37. Rg4 d4 38. Rg7+ Kf8 39. Qa2 Qe6 40. Qd2 Qf5 41. Rxc7 Bxf3 42. Qa2 Qe6 43. Qa3 Qh3 44. Nh7+ Ke8 45. Rxf3 Qh4 46. Rf2 Kd8 47. Rxa7 Rxa7 48. Qxa7 Qxh7 49. Rf8+ Rxf8 50. Qxh7 Re8 51. Qh4+ Re7 52. Qxd4+ Nd7 53. Qh4 Nxe5 54. Qh8+ Kd7 55. h4 Ke6 56. Qh6+ Kf5 57. Qg5+ Ke6 58. Kxg2 Nd7 59. h5 Nf6 60. h6 Rh7 61. Qc1 Kf5 62. Qe3 Kg6 63. Qxb6 Rxh6 64. Qc6 Kf5 65. Qf3+ Kg5 66. b6 Rg6 67. Kf1 Rg7 68. Qg3+ Ng4 69. Qb3 Kf4 70. Qb4+ Kg5 71. b7 Rf7+ 72. Ke2 Rxb7 73. Qxb7 Ne5 74. Ke3 Ng4+ 75. Kf3 Nf6 76. Qb5+

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 106 / 499 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): brqnknrb/pppppppp/8/8/8/8/PPPPPPPP/QNRNBBKR w CHbg - 0 1

Mirror twin: White 853 vs Black 547 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 322.