White 320 vs Black 128
White starts from setup 320 (BBNRQKRN), Black from setup 128 (BBNRQNKR). 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 #320 B B N R Q K R N
King on the f-file, rooks on d, 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 320 gives White +0.17 (Morozov Balance Index, 400M nodes).
Black: setup #128 B B N R Q N K R
King on the g-file, rooks on d, h, queen on the e-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 128 gives White +0.34 (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 54.
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 agreed early: from 100 thousand to 128 million nodes the evaluation never left ±15 cp.
For comparison, in symmetric play setup 320 gives White +0.17 and setup 128 gives White +0.34: 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 c4, and 2 first moves are within 10 cp of it.
Along the engine's main line (30 moves) the largest swing was 43 cp (around move 6), 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.
| Stage | Nodes | Depth | Eval, cp | Main line |
|---|---|---|---|---|
| S0 | 100 000 | 16 | -15 | 1. c4 c5 2. O-O h5 3. f4 h4 4. b3 b5 |
| S1 | 500 000 | 20 | -1 | 1. c4 c5 2. O-O h5 3. b3 h4 4. f3 e5 |
| S2 | 2 000 000 | 24 | -10 | 1. O-O c5 2. c4 b5 3. cxb5 d5 4. a4 a6 |
| S3 | 8 000 000 | 29 | +1 | 1. c4 c5 2. O-O b5 3. b3 bxc4 4. bxc4 Nd6 |
| S4 | 32 000 000 | 34 | -7 | 1. c4 c5 2. O-O h5 3. b3 h4 4. e4 b5 |
| S5 | 128 000 000 | 41 | -5 | 1. c4 c5 2. O-O b5 3. cxb5 d5 4. e3 Qxb5 |
| S6 | 400 000 000 | 49 | 0 | 1. c4 c5 2. O-O b5 3. cxb5 d5 4. e3 Qxb5 |
| S7 | 800 000 000 | 52 | 0 | 1. c4 c5 2. O-O b5 3. cxb5 d5 4. e3 Qxb5 |
| S8 | 1 600 000 000 | 54 | 0 | 1. c4 c5 2. O-O b5 3. cxb5 d5 4. e3 Qxb5 |
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: 0
- Lc0 0.32.1: -17
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 +142, Black +180, difference -38. 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 | -2 | 42 | 1. c4 c5 2. O-O b5 3. b3 bxc4 4. bxc4 h5 5. f4 Nb6 |
| 2 | -4 | 42 | 1. O-O c5 2. c4 b5 3. b3 bxc4 4. bxc4 h5 5. f4 Nb6 |
| 3 | -26 | 41 | 1. e4 c5 2. O-O e5 3. b3 Ne6 4. c3 b5 5. d4 cxd4 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 43 cp, mean 17.9 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | c4 | +11 | c5 | -6 |
| 2 | O-O | -4 | b5 | -14 |
| 3 | cxb5 | -15 | d5 | -18 |
| 4 | a4 | -16 | a6 | -9 |
| 5 | b4 | -16 | cxb4 | -20 |
| 6 | d4 | -17 | axb5 | -43 |
| 7 | Qxb4 | -34 | Bc6 | -38 |
| 8 | axb5 | -36 | Bxb5 | -39 |
| 9 | Bd3 | -30 | Nd6 | -33 |
| 10 | Bxb5 | -27 | Nxb5 | -27 |
| 11 | Nd3 | -25 | h5 | -26 |
| 12 | Rb1 | -23 | Nd6 | -27 |
| 13 | Rfc1 | -22 | Nc4 | -29 |
| 14 | Ng3 | -21 | Ng6 | -24 |
| 15 | Qb5 | -22 | Qf8 | -23 |
| 16 | Qc6 | -21 | Bd6 | -21 |
| 17 | Nf1 | -25 | e6 | -26 |
| 18 | Bc3 | -20 | Ne7 | -23 |
| 19 | Qa4 | -18 | Ba3 | -21 |
| 20 | Re1 | -22 | Rc8 | -25 |
| 21 | Nd2 | -15 | Nxd2 | -20 |
| 22 | Bxd2 | -16 | Nf5 | -19 |
| 23 | Bb4 | -14 | Bxb4 | -15 |
| 24 | Rxb4 | -12 | Qe7 | -12 |
| 25 | h3 | -8 | Kh7 | -8 |
| 26 | Reb1 | -5 | Nd6 | -6 |
| 27 | Nc5 | -7 | g6 | -3 |
| 28 | g3 | 0 | Ra8 | 0 |
| 29 | Qb3 | 0 | Ra7 | 0 |
| 30 | Rb8 | 0 | Rxb8 | 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 40.6 moves.
Sample game 1 (1/2-1/2)
1. O-O c5 2. c4 b6 3. f4 h5 4. b3 e6 5. d4 d5 6. cxd5 exd5 7. e3 cxd4 8. Bxd4 Ne6 9. Bb2 d4 10. Ne2 dxe3 11. Qc3 f6 12. Qxe3 Rxd1 13. Rxd1 Qc6 14. Qh3 Bxf4 15. Nf2 Be3 16. Kf1 Bxf2 17. Kxf2 O-O 18. b4 Ng5 19. Qb3+ Nf7 20. Nf4 Nd6 21. Rd4 Re8 22. Bg6 Re7 23. Nd5 Re5 24. Nf4 Re7 25. h4 Qc7 26. Kg1 b5 27. Qg3 Ne5 28. Nxh5 Nxg6 29. Qxg6 Ne8 30. Qd3 Qe5 31. Ng3 Qe1+ 32. Kh2 Bc6 33. Qg6 Qf2 34. Nf5 Re1 35. Nh6+ Kh8 36. Nf7+ Kg8 37. Nh6+ Kh8 38. Nf7+ Kg8
Sample game 2 (1/2-1/2)
1. c4 h5 2. b3 c5 3. O-O e5 4. e3 h4 5. f3 h3 6. g3 b6 7. Be4 d5 8. Bxd5 Bxd5 9. cxd5 Rxd5 10. d4 exd4 11. exd4 Qc6 12. dxc5 Rxd1 13. Qxd1 bxc5 14. Nd3 Rh6 15. Re1 Nb6 16. Nhf2 Bd6 17. Ne4 c4 18. bxc4 Nxc4 19. Qb3 Re6 20. Bd4 Rxe4 21. fxe4 Ne6 22. Qc3 Nxd4 23. Qxd4 Ne5 24. Qe3 Qc2 25. Nf2 Ng4 26. Qe2 Qxe2 27. Rxe2 Bc5 28. Rc2 Bd4 29. Rd2 Be3 30. Rc2 Nxf2 31. Rxf2 Kf8 32. Kf1 Bxf2 33. Kxf2 Ke7 34. Kf3 Ke6 35. Kf4 a5 36. e5 Kd5 37. Kf5 a4 38. a3 Kc5 39. g4 Kc4 40. g5 Kd5
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 320 / 128 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): bbnrqnkr/pppppppp/8/8/8/8/PPPPPPPP/BBNRQKRN w DGdh - 0 1
Mirror twin (the same position mirrored): White 351 vs Black 831.