White 111 vs Black 107

The two setups

White: setup #111 Q N R N K R B B

King on the e-file, rooks on c, f, 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 111 gives White +0.49 (Morozov Balance Index, 400M nodes).

Black: setup #107 Q N R N B K R B

King on the f-file, rooks on c, g, 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 107 gives White +0.31 (Morozov Balance Index, 400M nodes).

Why the pair is balanced

At the deepest rungs (400M, 800M, 1.6B, 3.2B nodes) the evaluation never left ±1 centipawns of equality, 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 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 ±6 cp.

For comparison, in symmetric play setup 111 gives White +0.49 and setup 107 gives White +0.31: 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 c4, and 2 first moves are within 10 cp of it.

Along the engine's main line (30 moves) the evaluation stayed within ±24 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 0, drawn 4, Black won 6 (White scored 20.0%).

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: -16

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 0, Black +26, difference -26. 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, 4 draws, 6 Black wins, White scored 20.0%.

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| 24 cp, mean 2.9 cp, final 0 cp.

Engine self-play

10 games at 500 000 nodes per move: White won 0, drawn 4, Black won 6 — White scored 20.0%. Average length 68.4 moves.

1. c4 g6 2. Nbc3 d6 3. g4 Bc6 4. f3 O-O 5. d4 b5 6. Nxb5 d5 7. f4 dxc4 8. Bxc6 Ndxc6 9. Rxc4 Qb7 10. Nbc3 Nd7 11. Qb1 Nb6 12. Rc5 Nxd4 13. Qe4 Qxe4 14. Nxe4 f5 15. gxf5 Rxf5 16. b3 a5 17. Ne3 Rxc5 18. Nxc5 Rf8 19. Ng2 Rf5 20. Bxd4 Bxd4 21. Ne6 Bc3+ 22. Kf2 Rf6 23. Rc1 Be5 24. Kf3 Rxe6 25. fxe5 Rxe5 26. Rxc7 Rf5+ 27. Kg3 Re5 28. Kf2 Nd5 29. Rc5 Rf5+ 30. Kg3 Rg5+ 31. Kf2 Rf5+ 32. Kg3 Nb4 33. Rxf5 gxf5 34. a3 Nc2 35. Kf4 Nxa3 36. Nh4 e6 37. Nf3 Nb1 38. Ke5 Kf7 39. h3 Nc3 40. Nd4 f4

1. g4 d6 2. c4 Bc6 3. Bxc6 bxc6 4. Nbc3 g6 5. Qb1 e5 6. f3 O-O 7. Bf2 Ne6 8. Ne3 Nd7 9. h4 a5 10. b3 Nf4 11. Bg3 Rb8 12. Rh1 Nc5 13. Kf1 Qb7 14. Qc2 Nfe6 15. h5 Bg7 16. Bf2 Nd4 17. Qd1 Qc8 18. d3 Qd7 19. Nc2 gxh5 20. gxh5 h6 21. e3 Nxc2 22. Rxc2 Ne6 23. Rg1 Kh8 24. Bh4 d5 25. Rcg2 f6 26. Rg6 Rf7 27. R1g3 d4 28. Ne4 Rbf8 29. exd4 Qxd4 30. Rg2 Nf4 31. Bf2 Qd8 32. Qd2 f5 33. Nc5 Re8 34. Rh2 Nxg6 35. hxg6 Rff8 36. Be3 f4 37. Bf2 Rf5 38. Ke2 Qa8 39. Ne4 a4 40. b4 Re6 41. a3 Rxg6 42. Qd1 Bf8 43. Qh1 Kh7 44. Qb1 Bd6 45. Ke1 Qg8 46. Qc2 Qa8 47. Kd2 Be7 48. Qb1 Qd8 49. Kc3 c5 50. b5 Bf8 51. Qb2 Rf7 52. Nxc5 Bxc5 53. Bxc5 Qg5 54. Kb4 Qf5 55. Qc2 Rd7 56. Rd2 h5 57. Qxa4 h4 58. Qc2 Rg3 59. Qd1 h3 60. a4 Rg5 61. Qb1 Rdg7 62. Qe1 Kg8 63. Qe4 Qxe4 64. dxe4 Rg2 65. Rd1 h2 66. Rh1 R7g3 67. a5 Rxf3 68. a6 Rb2+ 69. Ka5 Kf7 70. Ka4 Ra2+ 71. Kb4 Rb2+ 72. Ka4 Rc3 73. a7 Ra2+ 74. Kb4 Raa3 75. Bf2 Rcb3+ 76. Kc5 Rb2 77. Rxh2 Rxa7 78. Kc6 Ra4 79. c5 Rxe4 80. Kxc7 Rxb5 81. Rh4 Rb2 82. Bg3 Kf6 83. Rh3 fxg3 84. Rxg3 Rc4 85. Kc6 Rbc2 86. Kb5 e4 87. Rg4 Rxc5+ 88. Kb4 Ke5 89. Rg1 Rc8 90. Kb3 R2c6

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 111 / 107 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): qnrnbkrb/pppppppp/8/8/8/8/PPPPPPPP/QNRNKRBB w CFcg - 0 1

Mirror twin: White 848 vs Black 849 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 28.