White 459 vs Black 719

The two setups

White: setup #459 R N N K B Q R B

King on the d-file, rooks on a, g, queen on the f-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 459 gives White +0.32 (Morozov Balance Index, 400M nodes).

Black: setup #719 R K Q N N R B B

King on the b-file, rooks on a, f, queen on the c-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 719 gives White +0.25 (Morozov Balance Index, 400M nodes).

Why the pair is balanced

At the deepest rungs (400M, 800M, 1.6B, 3.2B nodes) the evaluation never left ±3 centipawns of equality, reaching search depth 61.

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 -16 and +3 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 459 gives White +0.32 and setup 719 gives White +0.25: 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 g4; the alternatives are slightly weaker but keep the game level.

Along the engine's main line (30 moves) the evaluation stayed within ±29 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: +1
• Lc0 0.32.1: +16

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 +76, Black +77, difference -1. 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| 29 cp, mean 12.5 cp, final -2 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 41.9 moves.

1. g4 g6 2. Nc3 f5 3. gxf5 Rxf5 4. e3 Nd6 5. N1e2 e5 6. O-O-O Ne6 7. d3 a5 8. Bd5 c6 9. Bxe6 Bxe6 10. Qg2 Qf8 11. Kb1 b6 12. f4 Kb7 13. fxe5 Rxe5 14. e4 a4 15. d4 Nc4 16. Rd3 Rea5 17. h4 Re8 18. Nd1 Rb5 19. Nec3 Rb4 20. Rf1 Qe7 21. Ne2 Rb5 22. Nec3 Rb4 23. Ne2 Rb5 24. Nec3

1. g4 f5 2. gxf5 g6 3. Nc3 Rxf5 4. f4 e5 5. Qh3 exf4 6. Qxf5 gxf5 7. Rxg8 Bxc3 8. Rxe8 Bf6 9. Rf8 Bg5 10. Rg8 Bf6 11. Rf8 Bg5 12. Rg8 h6 13. h4 Bf6 14. Nd3 d6 15. Nxf4 c6 16. c3 Kc7 17. Kc2 Qd7 18. Bg3 Qe7 19. Rg1 Rc8 20. Bd5 Nf7 21. Rxc8+ Kxc8 22. Be6+ Kb8 23. Bxf5 a5 24. a4 h5 25. Bd3 Ne5 26. Nxh5 Bxh4 27. Bxe5 dxe5 28. Rg4 Be1 29. Ng3 Bxg3 30. Rxg3 Qh4 31. Rg8+ Ka7 32. b3 Qe1 33. Bc4 Qa1 34. Rg7 Qa2+ 35. Kc1 Qa1+ 36. Kc2 e4 37. e3 Kb8 38. Rg8+ Ka7 39. Rg7 Kb8 40. Rd7 Qa2+

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 459 / 719 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): rkqnnrbb/pppppppp/8/8/8/8/PPPPPPPP/RNNKBQRB w AGaf - 0 1

Mirror twin: White 689 vs Black 432 — a different position (castling squares are fixed), not evaluated by the search.

Current place in the live balance rating: 64.