White 488 vs Black 466
White starts from setup 488 (QBRNBKNR), Black from setup 466 (BRNNKBRQ). 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 #488 Q B R N B K N 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 488 gives White +0.38 (Morozov Balance Index, 400M nodes).
Black: setup #466 B R N N K B R Q
King on the e-file, rooks on b, g, queen on the h-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 466 gives White +0.35 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation never left ±1 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 -3 and +17 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.
For comparison, in symmetric play setup 488 gives White +0.38 and setup 466 gives White +0.35: 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 d4, and 3 first moves are within 10 cp of it.
Along the engine's main line (30 moves) the evaluation stayed within ±23 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 | 14 | +16 | 1. b3 b5 2. h4 Nb6 3. f3 e6 4. c4 Ba3 |
| S1 | 500 000 | 18 | -3 | 1. b3 b5 2. h4 g6 3. Qxh8 Rxh8 4. c4 bxc4 |
| S2 | 2 000 000 | 24 | +5 | 1. b3 b5 2. h4 e6 3. a4 bxa4 4. Qxa4 c5 |
| S3 | 8 000 000 | 29 | +17 | 1. c4 g6 2. e3 c5 3. Ne2 Nd6 4. O-O Bg7 |
| S4 | 32 000 000 | 34 | +9 | 1. b3 b5 2. h4 h5 3. a4 g6 4. Qxh8 Rxh8 |
| S5 | 128 000 000 | 45 | 0 | 1. d4 g5 2. c4 h5 3. a4 Qxd4 4. Bc3 Qb6 |
| S6 | 400 000 000 | 46 | -1 | 1. c4 g6 2. e3 c5 3. Ne2 Nd6 4. O-O b6 |
| S7 | 800 000 000 | 53 | 0 | 1. c4 g6 2. e3 c5 3. Ne2 Nd6 4. O-O Bg7 |
| S8 | 1 600 000 000 | 56 | 0 | 1. c4 g6 2. e3 c5 3. Ne2 Nd6 4. O-O Bg7 |
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: +8
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 +65, Black +101, difference -36. 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 | +4 | 41 | 1. d4 |
| 2 | +2 | 41 | 1. c4 g6 2. e3 c5 3. Ne2 Nd6 4. O-O Bg7 5. f3 Ne6 |
| 3 | 0 | 40 | 1. b3 b5 2. h4 e6 3. Ne3 c5 4. f3 Nc6 5. Bg3 Nd6 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 23 cp, mean 3.2 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | c4 | +14 | g6 | +16 |
| 2 | e3 | -1 | c5 | +2 |
| 3 | Ne2 | -1 | Nd6 | +6 |
| 4 | h4 | +1 | b6 | -11 |
| 5 | Ndc3 | -1 | Bg7 | -6 |
| 6 | b3 | +3 | h5 | -3 |
| 7 | a4 | +9 | O-O | +3 |
| 8 | O-O | +11 | Nc6 | 0 |
| 9 | f3 | -1 | f5 | -15 |
| 10 | Qa3 | -18 | Nf7 | -23 |
| 11 | Bf2 | -13 | e5 | -11 |
| 12 | Rce1 | -9 | Nfd8 | -11 |
| 13 | a5 | -5 | Nxa5 | 0 |
| 14 | d4 | 0 | exd4 | 0 |
| 15 | exd4 | 0 | Nac6 | 0 |
| 16 | Nb5 | 0 | cxd4 | 0 |
| 17 | Nf4 | 0 | Qh6 | 0 |
| 18 | Nd5 | 0 | Ne6 | 0 |
| 19 | Bg3 | 0 | f4 | 0 |
| 20 | Bf2 | 0 | g5 | 0 |
| 21 | Nxa7 | 0 | Rbe8 | 0 |
| 22 | Nxc6 | 0 | Bxc6 | 0 |
| 23 | Ne7+ | 0 | Rxe7 | 0 |
| 24 | Qxe7 | 0 | g4 | 0 |
| 25 | Be4 | 0 | Bxe4 | 0 |
| 26 | Rxe4 | 0 | g3 | 0 |
| 27 | Qxd7 | 0 | gxf2+ | 0 |
| 28 | Rxf2 | 0 | Nc5 | 0 |
| 29 | Qd5+ | 0 | Kh8 | 0 |
| 30 | Re7 | 0 | Qg6 | 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 51.7 moves.
Sample game 1 (1/2-1/2)
1. d4 b5 2. a4 c5 3. dxc5 b4 4. b3 e6 5. c3 g6 6. Qb2 Nc6 7. cxb4 Qxb2 8. Nxb2 Nxb4 9. Nf3 Bg7 10. Nc4 Na6 11. Na5 Bb2 12. Rc4 Bd5 13. Rc2 Bf6 14. Rc1 Bb2 15. Rc2 Bf6 16. Bc3 Bxc3 17. Rxc3 Bxf3 18. gxf3 Ne7 19. c6 dxc6 20. Nxc6 Rc8 21. Bd3 Nb4 22. Nxe7 Kxe7 23. Rxc8 Rxc8 24. Bc4 Nc6 25. Kg2 Na5 26. Ba6 Rc3 27. b4 Nc6 28. Rb1 Ra3 29. Bb7 Nd8 30. Ba6 Nc6 31. Bb7 Nd8 32. Ba6
Sample game 2 (1/2-1/2)
1. d4 b5 2. a4 c5 3. dxc5 b4 4. b3 e6 5. c3 g6 6. Qb2 Nc6 7. cxb4 Qxb2 8. Nxb2 Nxb4 9. Nf3 Bg7 10. Nc4 Na6 11. Na5 Bb2 12. Rc4 Bd5 13. Rc2 Bf6 14. Rc1 Bb2 15. Rc2 Bf6 16. Bc3 Bxc3 17. Rxc3 Bxf3 18. gxf3 Ne7 19. c6 dxc6 20. Nxc6 Rc8 21. Bd3 Nb4 22. Nxe7 Kxe7 23. Rxc8 Rxc8 24. Bc4 Nc6 25. Kg2 Na5 26. Ba6 Rc3 27. b4 Nc6 28. Rb1 Ra3 29. Bb7 Nd8 30. Ba6 Nc6 31. Bb7 Nd8 32. Ba6
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 488 / 466 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): brnnkbrq/pppppppp/8/8/8/8/PPPPPPPP/QBRNBKNR w CHbg - 0 1
Mirror twin (the same position mirrored): White 573 vs Black 679.