White 79 vs Black 927

The two setups

White: setup #79 N N R K Q R B B

King on the d-file, rooks on c, f, queen on the e-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 79 gives White +0.36 (Morozov Balance Index, 400M nodes).

Black: setup #927 R K R Q N N B B

King on the b-file, rooks on a, c, queen on the d-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 927 gives White +0.52 (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 wandered between -17 and +12 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 79 gives White +0.36 and setup 927 gives White +0.52: 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 3 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 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.

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: +13

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 +109, Black +64, difference +45. 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.

Main-line play-out

30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 24 cp, mean 6.8 cp, final 0 cp.

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 41.8 moves.

1. O-O-O f5 2. d3 c5 3. c4 d5 4. cxd5 Bxd5 5. Nc3 f4 6. h4 g6 7. Bh2 Ne6 8. Qd2 N8c7 9. Bxf4 a5 10. Nc2 Ra6 11. g3 Nxf4 12. Qxf4 Rf6 13. Qg5 Bxh1 14. Rxh1 Rxf2 15. Rdf1 Rg2 16. Rhg1 Rxg1 17. Rxg1 Qd6 18. Rf1 Bf6 19. Qf4 O-O 20. Ne3 b5 21. Kc2 a4 22. h5 gxh5 23. Rh1 b4 24. Ne4 b3+ 25. axb3 axb3+ 26. Kd2 Qxf4 27. gxf4 Bxb2 28. Nxc5 Rb8 29. Rb1 Bf6 30. Rxb3 Rxb3 31. Nxb3 e5 32. Nc4 exf4 33. Ke1 Kf7 34. Kf2 Kg6 35. Nd6 Ne6 36. Kg2 h4 37. Ne4 Be7 38. Ned2 Ng5 39. Nd4 h3+ 40. Kh2 Bf6 41. N4f3 h6 42. Ne4 Bd8 43. Nf2 Bb6 44. Ne4 Bc7 45. Nfxg5 hxg5 46. Kxh3 Kf5 47. Kg2 g4 48. Nd2 Bb6

1. O-O-O f5 2. d3 g6 3. c4 d5 4. f4 c5 5. Nc2 Nd6 6. g4 dxc4 7. d4 Ne6 8. Nc3 a5 9. gxf5 gxf5 10. dxc5 Nxc5 11. Bd4 Bxd4 12. Nxd4 a4 13. a3 Nb3+ 14. Kb1 Ra5 15. Qf2 Qb6 16. Bf3 Nc5 17. Qe3 Nce4 18. Bxe4 Nxe4 19. Ka1 Bd5 20. Rg1 Nxc3 21. Qe5+ Qc7 22. Qxc7+ Rxc7 23. bxc3 Be4 24. Rg8+ Rc8 25. Rg7 e5 26. fxe5 Rxe5 27. Rxh7 Rg8 28. Rh6 Kc7 29. h4 Rg3 30. Kb2 Rh3 31. Rf1 Rd5 32. Rd1 Re5 33. Ne6+ Kb8 34. Rd8+ Ka7 35. Nd4 Rh2 36. Rd7 Rc5 37. Rd8 f4 38. Re8 Bc6 39. Re7 f3 40. Nxc6+ Rxc6 41. Rxc6 fxe2 42. Kc1 e1=Q+ 43. Rxe1 bxc6 44. Re4 Ka6 45. Rxc4 Kb5 46. Rb4+

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 79 / 927 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): rkrqnnbb/pppppppp/8/8/8/8/PPPPPPPP/NNRKQRBB w CFac - 0 1

Mirror twin: White 880 vs Black 32 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 349.