White 272 vs Black 705

The two setups

White: setup #272 B B N R K N R Q

King on the e-file, rooks on d, g, queen on the h-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 272 gives White +0.58 (Morozov Balance Index, 400M nodes).

Black: setup #705 B R K B Q N N R

King on the c-file, rooks on b, h, queen on the e-file; one 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 705 gives White +0.35 (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 54.

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 272 gives White +0.58 and setup 705 gives White +0.35: 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 largest swing was 43 cp (around move 5), ending at 0 cp — the position stays playable for both sides.

Engine self-play agrees: 10 games, White won 0, drawn 7, Black won 3 (White scored 35.0%).

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: 0
• Lc0 0.32.1: +14

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 +112, Black +65, difference +47. 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, 7 draws, 3 Black wins, White scored 35.0%.

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| 43 cp, mean 12.9 cp, final 0 cp.

Engine self-play

10 games at 500 000 nodes per move: White won 0, drawn 7, Black won 3 — White scored 35.0%. Average length 54.5 moves.

1. b4 e5 2. c4 b5 3. c5 g6 4. e4 a5 5. Ne3 f5 6. a3 Ne6 7. O-O Nf4 8. g3 Nh3+ 9. Kg2 Ng5 10. d3 Nf6 11. f3 Rf8 12. h4 Nf7 13. Kg1 Bb7 14. Ne2 axb4 15. axb4 Ra8 16. Bb2 Ra6 17. Rde1 Kb8 18. d4 fxe4 19. fxe4 h5 20. Qf3 g5 21. Nf5 Rg8 22. Bd3 d5 23. Nc3 dxe4 24. Nxe4 gxh4 25. Qe2 Bxe4 26. Bxe4 Nxe4 27. Qxe4 Ng5 28. Qg2 e4 29. Nxh4 Qe6 30. Re2 Qb3 31. Kh1 Qxb4 32. Rc2 Qb3 33. Bc1 Rf6 34. Rb2 Qd3 35. Rxf6 Bxf6 36. Be3 Nf3 37. Nxf3 Qxe3 38. Rxb5+ Kc8 39. Nh2 Rxg3 40. Qf1 Qxd4 41. c6 Kd8 42. Rb4 Qd6 43. Rxe4 Qxc6 44. Qf4 Be7 45. Qxg3 Qxe4+ 46. Nf3 Qg4 47. Qf2 Bd6 48. Qf1 Qe4 49. Qg2 Qg4 50. Qf1 h4 51. Qg2 Qg3 52. Nd2 Kd7 53. Nf1 Qxg2+ 54. Kxg2 Ke6 55. Ne3 Bf4 56. Nd1 Ke5 57. Kh3 Bg5 58. Kg4 Bf6 59. Kh3 Kd4 60. Kg2 c5 61. Nb2 Ke4 62. Nc4 Kd5 63. Ne3+ Kd4 64. Nc2+ Ke4 65. Na3 Kd5 66. Kh3 Bb2 67. Nb1 Kd4 68. Nd2 Kd3 69. Nb3 c4 70. Nc5+ Ke3 71. Na6 Bf6 72. Nc7 Ke4 73. Nb5 Kd5 74. Kg2 Bb2 75. Nc7+ Kd6 76. Na6 Ba3 77. Kh3 c3 78. Kxh4 c2

1. Ne3 e5 2. c4 b5 3. O-O bxc4 4. Nxc4 e4 5. d3 f5 6. h4 e3 7. b3 Nh6 8. Qh3 exf2+ 9. Rxf2 Rg8 10. e4 Qh5 11. Rdf1 g6 12. Rc2 Be7 13. Ne2 Ne6 14. Be5 Qxh4 15. Qxh4 Bxh4 16. Nd4 Nxd4 17. Bxd4 d5 18. exd5 Bxd5 19. Ne3 Be6 20. Bxa7 O-O-O 21. Rfc1 Rg7 22. Bb6 Bg3 23. d4 Bf4 24. Re1 Bg3 25. Rec1 Bf4 26. Re1 Re8 27. Nf1 Kd7 28. Ba5 Bd6 29. Rce2 Ng4 30. Bd2 Bf7 31. Rxe8 Bxe8 32. a4 Bf7 33. Bc2 c5 34. dxc5 Bxc5+ 35. Kh1 Bd5 36. a5 Nf2+ 37. Kh2 Ng4+ 38. Kh1 Re7 39. b4 Rxe1 40. Bxe1 Nf2+ 41. Kg1 Nd3+ 42. bxc5 Nxe1 43. Ne3 Bxg2 44. Bxf5+ gxf5

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 272 / 705 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): brkbqnnr/pppppppp/8/8/8/8/PPPPPPPP/BBNRKNRQ w DGbh - 0 1

Mirror twin: White 591 vs Black 443 — a different position (castling squares are fixed), not evaluated by the search.