White 109 vs Black 667
White starts from setup 109 (QNRBNKBR), Black from setup 667 (RNKRBNQB). In the encyclopedia since 2026-10-03: neither side starts better.
|cp| ≤ 5 at 400M · 800M · 1.6B · 4B nodes, two independent engines agree
The two setups
White: setup #109 Q N R B N K B R
King on the f-file, rooks on c, h, queen on the a-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 109 gives White +0.10 (Morozov Balance Index, 400M nodes).
Black: setup #667 R N K R B N Q B
King on the c-file, rooks on a, d, queen on the g-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 667 gives White +0.41 (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 ±4 centipawns of equality, reaching search depth 56.
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 shallow rungs wandered between -20 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 109 gives White +0.10 and setup 667 gives White +0.41: 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 d4; the alternatives are slightly weaker but keep the game level.
Along the engine's main line (30 moves) the largest swing was 67 cp (around move 9), ending at -5 cp — the position stays playable for both sides.
Engine self-play agrees: 10 games, White won 1, drawn 8, Black won 1 (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 | 15 | -9 | 1. h4 d6 2. c3 f5 3. Bh2 a5 4. d4 Nc6 |
| S1 | 500 000 | 21 | -3 | 1. h4 g6 2. Bh2 f5 3. c3 d6 4. a4 a5 |
| S2 | 2 000 000 | 23 | -18 | 1. d4 f5 2. h4 d6 3. c3 a5 4. Bh2 Nc6 |
| S3 | 8 000 000 | 29 | -20 | 1. a4 a5 2. f3 f5 3. c3 g5 4. Bf2 Nc6 |
| S4 | 32 000 000 | 33 | -17 | 1. h4 e5 2. c3 a5 3. e3 d6 4. d4 f5 |
| S5 | 128 000 000 | 44 | 0 | 1. c4 f5 2. Nc3 g6 3. f4 Nc6 4. Bf2 a5 |
| S6 | 400 000 000 | 48 | 0 | 1. c4 f5 2. Nc3 g6 3. f4 Nc6 4. Bf2 a5 |
| S7 | 800 000 000 | 53 | 0 | 1. c4 f5 2. d4 g5 3. d5 d6 4. Nc3 Ng6 |
| S8 | 1 600 000 000 | 54 | 0 | 1. c4 Nc6 2. Nc3 g6 3. f4 f5 4. Bf2 a5 |
| S9 | 3 200 000 000 | 56 | +4 | 1. c4 f5 2. d4 g5 3. d5 d6 4. Nc3 Ng6 |
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 | not checked |
| 8 000 000 000 | not checked |
| 16 000 000 000 | not checked |
This pair held exactly 0.00 up to 1 600 000 000 nodes.
Independent engines, run on the same position:
- Berserk 14: -1
- Lc0 0.32.1: +3
Independent confirmations: 2 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 +94, difference -62. A balanced pair needs White's setup to be weaker by about the price of the first move.
Extended self-play: 10 games, 1 White wins, 8 draws, 1 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 | +22 | 40 | 1. d4 f5 2. c3 e5 3. h4 d6 4. Bh2 g6 5. e3 a5 |
| 2 | +11 | 39 | 1. c4 f5 2. d4 g5 3. d5 d6 4. Nc3 Ng6 5. Qb1 Bd7 |
| 3 | +6 | 40 | 1. c4 f5 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 67 cp, mean 29.1 cp, final -5 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | a4 | -22 | a5 | -24 |
| 2 | c3 | -22 | g5 | -18 |
| 3 | Qa2 | -20 | d5 | -26 |
| 4 | h4 | -29 | gxh4 | -25 |
| 5 | Rxh4 | -29 | e5 | -29 |
| 6 | e3 | -18 | f5 | -45 |
| 7 | b4 | -42 | Nbd7 | -42 |
| 8 | d4 | -36 | f4 | -42 |
| 9 | exf4 | -40 | Ng6 | -67 |
| 10 | Rh1 | -48 | Nxf4 | -45 |
| 11 | Bh2 | -47 | Qf8 | -46 |
| 12 | bxa5 | -45 | Rxa5 | -55 |
| 13 | Nd2 | -44 | Nb6 | -42 |
| 14 | Bxf4 | -43 | Qxf4 | -48 |
| 15 | Nd3 | -46 | Qf5 | -40 |
| 16 | Nxe5 | -41 | Bxe5 | -45 |
| 17 | dxe5 | -34 | Qxe5 | -32 |
| 18 | Nf3 | -36 | Qf6 | -36 |
| 19 | Qd2 | -27 | Bg6 | -31 |
| 20 | Kg1 | -22 | Nc4 | -32 |
| 21 | Qd4 | -27 | Qe7 | -29 |
| 22 | Bc2 | -25 | Bxc2 | -32 |
| 23 | Rxc2 | -17 | Rxa4 | -17 |
| 24 | Qd1 | -19 | Ra6 | -24 |
| 25 | Re2 | -16 | Qf7 | -12 |
| 26 | Rh4 | -13 | h6 | -15 |
| 27 | Qe1 | -6 | Kb8 | -14 |
| 28 | Ne5 | -12 | Nxe5 | 0 |
| 29 | Rxe5 | 0 | Qf6 | -5 |
| 30 | Rd4 | 0 | Ra5 | -5 |
Engine self-play
10 games at 500 000 nodes per move: White won 1, drawn 8, Black won 1 — White scored 50.0%. Average length 52.3 moves.
Sample game 1 (1/2-1/2)
1. c4 d6 2. f3 Nc6 3. Nc3 a5 4. Qb1 g6 5. Bf2 f5 6. O-O f4 7. Nd3 Ne6 8. e3 g5 9. Bc2 Bg6 10. Nd5 Qf7 11. Rfe1 Rg8 12. Kh1 Ned8 13. exf4 e6 14. Nc3 gxf4 15. Nb5 e5 16. a3 Ne6 17. b4 Qg7 18. Rg1 Qh6 19. bxa5 Rxa5 20. a4 e4 21. fxe4 Ncd4 22. Rce1 f3 23. Bd1 Rf8 24. Qb4 Nc6 25. Qb3 Ned4 26. Qa3 b6 27. Be3 Qg7 28. Nf2 Kb7 29. Bxd4 fxg2+ 30. Rxg2 Nxd4 31. Qe3 Nxb5 32. cxb5 Qd4 33. Qxd4 Bxd4 34. Nh3 Raa8 35. Ng5 Rae8 36. Bb3 Rf6 37. Bd5+ Kb8 38. h3 Kc8 39. Rc1 Bc5 40. Bc6 Ref8 41. Bd5 Re8 42. Bc6 Ref8 43. Bd5
Sample game 2 (1/2-1/2)
1. c4 f5 2. e3 d6 3. h4 e5 4. Bh2 Nc6 5. b3 a5 6. Nc3 h6 7. Qb1 g6 8. a3 Kb8 9. O-O Ne7 10. Be2 g5 11. h5 f4 12. b4 Bf7 13. c5 dxc5 14. bxc5 Be8 15. Nb5 Ne6 16. Bc4 Bc6 17. Nd3 Nd5 18. Qb2 e4 19. Ne5 Bxb5 20. Bxb5 Qg7 21. Bc6 Nb4 22. axb4 Qxe5 23. Qxe5 Bxe5 24. Bxe4 Rxd2 25. b5 Bb2 26. Rce1 Ka7 27. exf4 Nxf4 28. Bf3 Rad8 29. Re7 R2d7 30. Re4 Rd2 31. Re7 R2d7 32. Re4 Rd2
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 109 / 667 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): rnkrbnqb/pppppppp/8/8/8/8/PPPPPPPP/QNRBNKBR w CHad - 0 1
Mirror twin (the same position mirrored): White 856 vs Black 193.