White 335 vs Black 143

The two setups

White: setup #335 N R Q K R N B B

King on the d-file, rooks on b, e, queen on the c-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 335 gives White +0.37 (Morozov Balance Index, 400M nodes).

Black: setup #143 N R Q N K R B B

King on the e-file, rooks on b, f, queen on the c-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 143 gives White +0.18 (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 64.

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 -19 and +11 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 335 gives White +0.37 and setup 143 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.

White is not forced into a single path: the best first move is f4, and 3 first moves are within 10 cp of it.

Along the engine's main line (30 moves) the evaluation stayed within ±20 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 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 +63. 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: +1
• Lc0 0.32.1: +11

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 +14, difference -14. 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, 160 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| 20 cp, mean 4.0 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 42.2 moves.

1. f4 Nb6 2. c4 f5 3. d3 g5 4. fxg5 d5 5. c5 Nd7 6. g3 e5 7. b4 e4 8. d4 c6 9. Be3 b6 10. Nc2 Ne6 11. Bg2 a5 12. a3 axb4 13. axb4 bxc5 14. bxc5 Rxb1 15. Qxb1 Qa6 16. Nd2 Ke7 17. O-O Rb8 18. Qa1 Nexc5 19. Bf4 Qxa1 20. Rxa1 Rb2 21. dxc5 Rxc2 22. Ra8 Bd4+ 23. e3 Bxc5 24. Nb3 Bf7 25. Bh3 Ne5 26. Bxe5 Bxe3+ 27. Kf1 d4 28. Ra7+ Ke8 29. Ra8+ Ke7 30. Ra7+ Kf8 31. Ra8+

1. f4 Nb6 2. g3 f5 3. Nb3 d6 4. c3 g6 5. Qc2 c5 6. d4 cxd4 7. Nxd4 Nc6 8. O-O-O Nxd4 9. Bxd4 Bxd4 10. Rxd4 Qc7 11. e4 O-O-O 12. exf5 Rxf5 13. Nd2 Kb8 14. Qd3 Rff8 15. Qe2 Rde8 16. Re4 e6 17. Re3 a6 18. h4 Re7 19. b3 Nd7 20. Kb2 Rfe8 21. Qd1 e5 22. fxe5 Nxe5 23. Ne4 d5 24. Nf6 Nc4+ 25. bxc4 Rxe3 26. Nxe8 Qxg3 27. Rxe3 Qxe3 28. cxd5 Qxe8 29. Qf3 Qb5+ 30. Kc2 Qa4+ 31. Kb2 Qb5+ 32. Kc2 Qa4+ 33. Kd3 Qxh4 34. Qf8+ Ka7 35. Qc5+ Ka8 36. Qf8+ Ka7 37. Qc5+ Ka8 38. Qc8+ Ka7

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 335 / 143 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): nrqnkrbb/pppppppp/8/8/8/8/PPPPPPPP/NRQKRNBB w BEbf - 0 1

Mirror twin: White 336 vs Black 816 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 58.