White 33 vs Black 483

The two setups

White: setup #33 B N N B Q R K R

King on the g-file, rooks on f, 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 33 gives White +0.39 (Morozov Balance Index, 400M nodes).

Black: setup #483 B Q R N K N R B

King on the e-file, rooks on c, g, queen on the b-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 483 gives White +0.10 (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 -25 and 0 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 33 gives White +0.39 and setup 483 gives White +0.10: with both sides on the same rank the first move is worth something. In this pair Black's own setup absorbs that edge completely.

The engine's first choice for White is b4; the alternatives are slightly weaker but keep the game level.

Along the engine's main line (10 moves) the evaluation stayed within ±0 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 +175. 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: -9

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 +100, Black +150, difference -50. 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, 158 draws, 2 Black wins, White scored 49.4%.

Best first moves

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

Main-line play-out

10 moves, 5 000 000 nodes per half-move. Largest |evaluation| 0 cp, mean 0.0 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 37.9 moves.

1. b3 c5 2. c4 a6 3. e3 b5 4. d3 h5 5. h4 g6 6. Bxh8 Rxh8 7. Nd2 Nde6 8. Bf3 Nh7 9. Bxa8 Qxa8 10. d4 cxd4 11. exd4 bxc4 12. bxc4 Nf6 13. d5 Ng7 14. Nd3 Nf5 15. Rh3 Ng4 16. Qc1 f6 17. Nf4 Kf7 18. c5 Rb8 19. Rc3 Rb4 20. Nc4 Nxh4 21. c6 dxc6 22. Qe1 Qb8 23. Qe6+ Kg7 24. Qxe7+ Kh6 25. d6 Nf5 26. Qc7 Nd4 27. Rcc1 Ne5 28. Qe7 Qd8 29. Rfd1 Qxe7 30. dxe7 Nf5 31. Nxe5 fxe5 32. Nd3 Rb5 33. Re1 Re8 34. Nxe5 Rxe7 35. Nxc6 Rxe1+ 36. Rxe1 g5 37. a4 Rc5 38. Re6+ Kg7 39. Nb4 g4 40. Nd3 Ra5 41. Nf4 h4 42. Rg6+ Kh7

1. b4 c5 2. bxc5 Nde6 3. e3 Nxc5 4. f3 b5 5. Qg3 Qb6 6. Re1 Nfe6 7. Qf2 O-O 8. h4 h5 9. O-O Nb7 10. d3 Nd6 11. e4 Qxf2+ 12. Rxf2 a5 13. Ne2 g6 14. Bxh8 Kxh8 15. c3 b4 16. c4 Nc5 17. Bc2 e5 18. f4 f6 19. Nd2 Kg7 20. Nb3 Ndb7 21. Nd2 Nd6 22. Nb3 Ndb7 23. Nd2

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 33 / 483 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): bqrnknrb/pppppppp/8/8/8/8/PPPPPPPP/BNNBQRKR w FHcg - 0 1

Mirror twin: White 923 vs Black 563 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 6.