White 7 vs Black 512
White starts from setup 7 (QNBNRKRB), Black from setup 512 (BBRNQKNR). In the encyclopedia since 2026-10-21: neither side starts better.
|cp| ≤ 5 at 400M · 800M · 1.6B · 4B nodes, two independent engines agree
How to play with different setups
White sets up the pieces by position No. 7, Black by position No. 512, mirrored on their own side; the pawns stand as usual.
Moves as usual: White starts; everything else follows the Chess960 rules.
The two setups
White: setup #7 Q N B N R K R B
King on the f-file, rooks on e, g, queen on the a-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 7 gives White +0.24 (Morozov Balance Index, 400M nodes).
Black: setup #512 B B R N Q K N R
King on the f-file, rooks on c, h, queen on the e-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 512 gives White +0.16 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation never left ±3 centipawns of equality, reaching search depth 52.
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 -13 and +21 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.
For comparison, in symmetric play setup 7 gives White +0.24 and setup 512 gives White +0.16: 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 (30 moves) the evaluation stayed within ±16 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.
| Stage | Nodes | Depth | Eval, cp | Main line |
|---|---|---|---|---|
| S0 | 100 000 | 17 | +21 | 1. g3 c5 2. b3 Nc6 3. Ne3 b6 4. Bb2 f6 |
| S1 | 500 000 | 21 | -3 | 1. g3 c5 2. b3 Nc6 3. Ne3 b6 4. Bb2 f6 |
| S2 | 2 000 000 | 24 | -13 | 1. g3 c5 2. c4 Nc6 3. b3 b6 4. f4 e6 |
| S3 | 8 000 000 | 31 | -5 | 1. g3 c5 2. b3 Nc6 3. c4 b6 4. f4 e6 |
| S4 | 32 000 000 | 36 | 0 | 1. g3 c5 2. b3 Nc6 3. e4 f6 4. Ne3 b6 |
| S5 | 128 000 000 | 39 | +7 | 1. g3 c5 2. b3 Nc6 3. Bb2 f6 4. e4 b6 |
| S6 | 400 000 000 | 44 | 0 | 1. g3 c5 2. d3 f5 3. Nd2 Nf6 4. e4 Qh5 |
| S7 | 800 000 000 | 48 | +3 | 1. g3 c5 2. e4 h5 3. d3 b6 4. Nd2 e6 |
| S8 | 1 600 000 000 | 52 | 0 | 1. g3 c5 2. b3 Nc6 3. c4 b6 4. e3 e6 |
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.
| Nodes | Eval, cp |
|---|---|
| 4 000 000 000 | 0 |
| 8 000 000 000 | not checked |
| 16 000 000 000 | not checked |
This pair stays within the ±5 cp corridor up to 4 000 000 000 nodes.
Independent engines, run on the same position:
- Berserk 14: +6
- 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 +32, Black +157, difference -125. 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.
| # | Eval, cp | Depth | Main line |
|---|---|---|---|
| 1 | +20 | 42 | 1. g3 c5 2. b3 Nc6 3. Bb2 f6 4. e4 e6 5. Ne3 Nge7 |
| 2 | -1 | 41 | 1. b3 d5 2. g3 Nf6 3. d4 b5 4. c4 bxc4 5. bxc4 Ne6 |
| 3 | -18 | 41 | 1. e4 d5 2. exd5 c6 3. d6 Bxd6 4. g3 c5 5. b3 Qd7 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 16 cp, mean 1.3 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | g3 | 0 | c5 | -11 |
| 2 | b3 | -11 | Nc6 | -9 |
| 3 | e4 | -16 | f6 | -12 |
| 4 | d3 | -8 | Qh5 | 0 |
| 5 | Bg2 | 0 | Nd4 | 0 |
| 6 | Ne3 | 0 | Nh6 | 0 |
| 7 | h3 | 0 | f5 | 0 |
| 8 | Bb2 | 0 | O-O | 0 |
| 9 | Bxd4 | 0 | cxd4 | 0 |
| 10 | Qxd4 | 0 | f4 | 0 |
| 11 | gxf4 | 0 | Bxf4 | 0 |
| 12 | Qxd7 | 0 | b6 | 0 |
| 13 | Qxe7 | 0 | Rc7 | 0 |
| 14 | Qb4 | 0 | Nf7 | 0 |
| 15 | Re2 | 0 | Ne5 | 0 |
| 16 | Nc3 | 0 | Rc5 | 0 |
| 17 | Ncd1 | +10 | Bb7 | 0 |
| 18 | c4 | 0 | Bxe3 | 0 |
| 19 | Nxe3 | 0 | Nxd3 | 0 |
| 20 | Qc3 | 0 | Nf4 | 0 |
| 21 | Rd2 | 0 | Rg5 | 0 |
| 22 | h4 | 0 | Rg6 | 0 |
| 23 | Nf5 | 0 | Rxf5 | 0 |
| 24 | exf5 | 0 | Qxf5 | 0 |
| 25 | Rd8+ | 0 | Kf7 | 0 |
| 26 | Qe1 | 0 | Bxg2+ | 0 |
| 27 | Rxg2 | 0 | Re6 | 0 |
| 28 | Qd1 | 0 | Nxg2 | 0 |
| 29 | Rd7+ | 0 | Ke8 | 0 |
| 30 | Rd8+ | 0 | Kf7 | 0 |
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 44.2 moves.
Sample game 1 (1/2-1/2)
1. e4 f6 2. g3 c5 3. d3 h5 4. Nd2 Nc6 5. Nf3 b6 6. b3 e6 7. Bb2 Nge7 8. Ne3 Qf7 9. a3 Bb7 10. b4 cxb4 11. axb4 Nxb4 12. Qa4 a5 13. Ba3 O-O 14. Bxb4 Bc6 15. Qa3 axb4 16. Qxb4 f5 17. O-O f4 18. Nc4 Ng6 19. Rb1 Qf6 20. Nxb6 Rcd8 21. Qc5 Ne5 22. Nxe5 Qxe5 23. Qxe5 Bxe5 24. Nc4 Bd4 25. Nd2 Bc3 26. Nf3 fxg3 27. hxg3 Rb8 28. Rb3 Rxb3 29. cxb3 Rb8 30. Rb1 Ba4 31. Kf1 Rxb3 32. Rxb3 Bxb3 33. Ke2 Ba4 34. Ke3 e5 35. Ng5 Bd1 36. f4 d6 37. Nf3 Bb2 38. Kd2 Ba4 39. Bg2 g6 40. Bh3 Kf7
Sample game 2 (1/2-1/2)
1. b3 d5 2. Bb2 Ne6 3. g3 Qd7 4. d4 b5 5. c4 bxc4 6. bxc4 Nf6 7. cxd5 Bxd5 8. Bxd5 Qxd5 9. Nd2 c5 10. e4 Qg5 11. Qc1 O-O 12. d5 Nd4 13. f4 Qh5 14. Nf2 Qxh2 15. Qd1 Qh5 16. Nc4 Qxd1 17. Rxd1 Nh5 18. Nd3 Nf6 19. Nf2 Nh5 20. Nd3 Nf6
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 7 / 512 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): bbrnqknr/pppppppp/8/8/8/8/PPPPPPPP/QNBNRKRB w EGch - 0 1
Mirror twin: White 946 vs Black 543 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 88.