White 65 vs Black 213

The two setups

White: setup #65 B N N B R K Q R

King on the f-file, rooks on e, h, queen on the g-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 65 gives White +0.26 (Morozov Balance Index, 400M nodes).

Black: setup #213 N Q B B R K N R

King on the f-file, rooks on e, h, queen on the b-file; no 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 213 gives White +0.28 (Morozov Balance Index, 400M nodes).

Why the pair is balanced

At the deepest rungs (400M, 800M, 1.6B, 3.2B 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 -9 and +43 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 65 gives White +0.26 and setup 213 gives White +0.28: 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 f4, and 2 first moves are within 10 cp of it.

Along the engine's main line (29 moves) the evaluation stayed within ±23 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 9, Black won 1 (White scored 45.0%).

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 16 000 000 000 nodes.

Swap the two setups, giving White the black back rank and Black the white one, and the evaluation jumps to +83. The same two armies dealt the other way round are no longer balanced at all: that is how precisely this pair pays for the first move.

Independent engines, run on the same position:

• Berserk 14: 0
• Lc0 0.32.1: +6

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 +55, Black +78, difference -23. A balanced pair needs White's setup to be weaker by about the price of the first move.

Extended self-play: 160 games, 0 White wins, 155 draws, 5 Black wins, White scored 48.4%.

Best first moves

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

Main-line play-out

29 moves, 5 000 000 nodes per half-move. Largest |evaluation| 23 cp, mean 4.6 cp, final 0 cp.

Engine self-play

10 games at 500 000 nodes per move: White won 0, drawn 9, Black won 1 — White scored 45.0%. Average length 41.0 moves.

1. f4 c6 2. Qf2 Nf6 3. b4 d5 4. O-O Qd6 5. a3 Ne4 6. Qf3 Bb6+ 7. e3 h5 8. Qe2 Bg4 9. Qd3 Qg6 10. Nc3 Bf5 11. Qe2 Nxc3 12. Bxc3 Bxc2 13. Bxc2 Qxc2 14. Nd3 f6 15. Ra1 Qa4 16. f5 Nc7 17. Nf4 Rh6 18. Bd4 e5 19. fxe6 Qc2 20. Rac1 Qe4 21. d3 Qf5 22. Bxb6 axb6 23. e4 dxe4 24. dxe4 Qe5 25. Qf2 Nxe6 26. Nxe6+ Rxe6 27. Qxb6 Re7 28. b5 cxb5 29. Qc5 Qe6 30. Rf4 Qe5 31. Qxe5 Rxe5 32. Rc7 Rg6 33. Rf5 Rxf5 34. exf5 Rg5 35. Rc5 Rg4 36. Rxb5 Ra4 37. Rxb7 Rxa3 38. Rb8+ Ke7 39. Rb7+ Kf8 40. Rb8+ Ke7 41. Rg8 Ra1+ 42. Kf2

1. e4 e5 2. h4 d6 3. b3 c6 4. g4 Nc7 5. d4 exd4 6. Bxd4 Nf6 7. f3 O-O 8. Bxa7 Qa8 9. Bf2 Ne6 10. Qh2 d5 11. e5 Nd7 12. O-O f6 13. exf6 Nxf6 14. Bg3 b5 15. Bd6 Be7 16. Bxe7 Rxe7 17. Nd2 Qa7+ 18. Kh1 c5 19. f4 g6 20. Nd3 c4 21. Ne5 Bb7 22. f5 gxf5 23. gxf5 Ng7 24. bxc4 dxc4+ 25. Bf3 Rfe8 26. Qg1 Qxg1+ 27. Kxg1 Bxf3 28. Nexf3 Rxe1 29. Nxe1 Re2 30. Nef3 Nxf5 31. Rf2 Re7 32. Ng5 Re5 33. Ndf3 Rd5 34. Ne6 Kf7 35. Re2 Ng4 36. Nfg5+ Kg8 37. Kg2 Rd1 38. Ne4 Nge3+ 39. Kf3 Rf1+ 40. Nf2 Nd1 41. h5 Kf7 42. Ng5+ Kg7 43. Kg4 Nh6+ 44. Kf3 Nf5 45. Kg4 Nd4 46. Re7+ Kf6 47. Rf7+ Ke5 48. Nxd1 Rxd1 49. Re7+ Kd5 50. Rxh7 Rg1+ 51. Kf4

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 65 / 213 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): nqbbrknr/pppppppp/8/8/8/8/PPPPPPPP/BNNBRKQR w EHeh - 0 1

Mirror twin: White 891 vs Black 650 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 18.