White 166 vs Black 533

The two setups

White: setup #166 N R B N K B Q R

King on the e-file, rooks on b, h, queen on the g-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 166 gives White +0.31 (Morozov Balance Index, 400M nodes).

Black: setup #533 R N B B K Q N R

King on the e-file, rooks on a, h, queen on the f-file; no 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 533 gives White +0.39 (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 60.

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 0 and +18 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 166 gives White +0.31 and setup 533 gives White +0.39: 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 Nc3, and 3 first moves are within 10 cp of it.

Along the engine's main line (30 moves) the evaluation stayed within ±21 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: -1

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 -15, Black +25, difference -40. 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| 21 cp, mean 2.3 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 35.2 moves.

1. d4 d5 2. f3 f5 3. Nc3 Nf6 4. Nb3 Qf7 5. Bf4 O-O 6. e3 c6 7. h4 Nh5 8. Bh2 f4 9. Ne2 e5 10. O-O-O Bb6 11. g4 fxg3 12. Nxg3 Nd7 13. a4 exd4 14. a5 Bd8 15. Nxd4 Ne5 16. Ngf5 Bxf5 17. Bxe5 Bg6 18. a6 bxa6 19. Bh3 Qb7 20. Qg4 Re8 21. f4 Bf6 22. Qd7 Qxd7 23. Bxd7 Bxe5 24. fxe5 Rxe5 25. Bxc6 Rf8 26. Rhg1 Nf6 27. Rg5 Rxe3 28. Nf5 Re2 29. Bxd5+ Kh8 30. Bb7 Rf2 31. Nd4 Rd8 32. Rc5 Bh5 33. Rd3 Rb8 34. Rc8+ Rxc8 35. Bxc8 Rf4 36. Ne6 Rf1+ 37. Kd2 Nd5 38. c3 Rd1+ 39. Kc2 Rxd3 40. Kxd3 Bg4 41. Nc7 Nb4+ 42. Kc4 Bxc8 43. Kxb4 Kg8 44. Kc5 Kf7 45. Kd6 a5 46. c4 h6

1. Nc3 e5 2. f4 Qe7 3. e4 d6 4. d3 c6 5. Qf2 Bb6 6. Be3 Nh6 7. Be2 exf4 8. Qxf4 O-O 9. O-O f5 10. Bxb6 axb6 11. Rbe1 fxe4 12. Qxe4 Rxf1+ 13. Bxf1 Qf8 14. Nb3 Nd7 15. a3 d5 16. Qe6+ Nf7 17. Qe3 b5 18. Nd1 Nf6 19. Nf2 Bd7 20. Qd2 Re8 21. Rxe8 Qxe8 22. Qe2 Nd6 23. Qxe8+ Bxe8 24. g3 Kf7 25. Be2 Nd7 26. c3 g5 27. Nd1 Kf6 28. Kf2 Ne5 29. Nc5 h5 30. Ne3 Bg6 31. d4 Nef7 32. h3 Kg7 33. Ne6+ Kf6 34. Nc5 Kg7 35. Ne6+ Kf6

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 166 / 533 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): rnbbkqnr/pppppppp/8/8/8/8/PPPPPPPP/NRBNKBQR w BHah - 0 1

Mirror twin: White 790 vs Black 522 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 36.