White 247 vs Black 784

The two setups

White: setup #247 N R B K Q N R B

King on the d-file, rooks on b, g, queen on the e-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 247 gives White +0.18 (Morozov Balance Index, 400M nodes).

Black: setup #784 B B R Q K N R N

King on the e-file, rooks on c, g, queen on the d-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 784 gives White +0.58 (Morozov Balance Index, 400M nodes).

Why the pair is balanced

At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation is exactly 0.00 each time, reaching search depth 55.

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 -3 and +20 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.

For comparison, in symmetric play setup 247 gives White +0.18 and setup 784 gives White +0.58: 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 g3; the alternatives are slightly weaker but keep the game level.

Along the engine's main line (28 moves) the largest swing was 33 cp (around move 3), ending at 0 cp — the position stays playable for both sides.

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: -5

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 +58, Black +98, 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

28 moves, 5 000 000 nodes per half-move. Largest |evaluation| 33 cp, mean 7.5 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 41.8 moves.

1. g3 d5 2. f4 c5 3. b4 cxb4 4. Rxb4 Bd6 5. Rb1 Nd7 6. Bxd5 O-O 7. Ne3 Nf6 8. Bg2 e5 9. Rb3 Re8 10. Nf5 Bf8 11. fxe5 Rxe5 12. Rf1 Qa5 13. e4 Qxa2 14. Bb2 Ree8 15. Qe3 Ng6 16. Nh6+ gxh6 17. Rxf6 Bg7 18. Kc1 Ne5 19. Bxe5 Rxe5 20. Ra3 Qc4 21. Rf4 b6 22. c3 a5 23. Nc2 Qc7 24. d4 Re7 25. Qd3 Ree8 26. Bh3 Rb8 27. c4 Red8 28. Rc3 Bc6 29. Qe3 Be8 30. e5 Qe7 31. Qe4 a4 32. Rcf3 h5 33. Rf6 b5 34. Bf5 Bxf6 35. Bxh7+ Kf8 36. Rxf6 Qb7 37. Qe3 bxc4 38. e6 Qb1+ 39. Kd2 c3+ 40. Qxc3 Kg7 41. exf7 Bd7 42. Qe3 Kxf6 43. Qe5+ Kxf7

1. d4 d5 2. Be3 Nd7 3. O-O-O b6 4. g4 c5 5. h4 cxd4 6. Rxd4 e6 7. h5 g5 8. Kb1 f6 9. Bc1 O-O 10. Rd1 Nf7 11. Ng3 Qe7 12. Nb3 Nc5 13. Nd4 Ne4 14. Nxe4 dxe4 15. e3 Ne5 16. Qe2 h6 17. b3 Bd6 18. Bb2 Bb4 19. a4 Bc3 20. Bxc3 Rxc3 21. Nb5 Rc5 22. Rd4 f5 23. gxf5 exf5 24. Rgd1 a6 25. Na3 Rc7 26. Nc4 Nxc4 27. Rxc4 Bc6 28. Rcd4 b5 29. a5 g4 30. R1d2 Be8 31. Qd1 Rf6 32. Bg2 Rfc6 33. Bf1 Bf7 34. Rd8+ Kg7 35. R2d6 Qe5 36. c4 Qc3 37. Rxc6 Rxc6 38. cxb5 axb5 39. Rd7 Kg8 40. Rxf7 Kxf7 41. Bxb5 Rc7 42. Qd5+ Ke7 43. Bc4

Play it in the CH960 app

Open this page on a phone with the CH960 app installed, or find pair 247 / 784 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): bbrqknrn/pppppppp/8/8/8/8/PPPPPPPP/NRBKQNRB w BGcg - 0 1

Mirror twin: White 610 vs Black 175 — a different position (castling squares are fixed), not evaluated by the search.