White 65 vs Black 103
White starts from setup 65 (BNNBRKQR), Black from setup 103 (QNBRNKRB). 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. 65, Black by position No. 103, 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 #65 B N N B R K Q R
King on the f-file, rooks on e, h, queen on the g-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 65 gives White +0.26 (Morozov Balance Index, 400M nodes).
Black: setup #103 Q N B R N K R B
King on the f-file, rooks on d, 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 103 gives White +0.17 (Morozov Balance Index, 400M nodes).
Why the pair is balanced
At the deepest rungs (400M, 800M, 1.6B nodes) the evaluation never left ±5 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 same corridor is required at every deeper budget (8 G, 16 G) at which the pair has been evaluated.
The shallow rungs wandered between -6 and +25 cp before settling — a reminder that quick engine checks overstate imbalances, and why the ladder goes deep.
For comparison, in symmetric play setup 65 gives White +0.26 and setup 103 gives White +0.17: 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 b4; the alternatives are slightly weaker but keep the game level.
Along the engine's main line (30 moves) the largest swing was 31 cp (around move 5), 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 | 13 | +1 | 1. e4 b6 2. h4 g6 3. Nc3 c5 4. b3 Nc6 |
| S1 | 500 000 | 17 | -2 | 1. b3 d5 2. f4 Nf6 3. Qf2 g6 4. Qh4 c5 |
| S2 | 2 000 000 | 22 | -6 | 1. b3 d5 2. d3 c5 3. f4 d4 4. Qf2 g6 |
| S3 | 8 000 000 | 28 | +11 | 1. b4 a5 2. b5 c6 3. c4 d5 4. cxd5 Rxd5 |
| S4 | 32 000 000 | 33 | +25 | 1. b4 d5 2. f3 Nc6 3. Nd3 a6 4. a4 Qa7 |
| S5 | 128 000 000 | 39 | +7 | 1. b4 d5 2. f3 Nc6 3. Nd3 a6 4. e4 dxe4 |
| S6 | 400 000 000 | 48 | -5 | 1. b4 d5 2. f3 Nc6 3. b5 Na5 4. e4 b6 |
| S7 | 800 000 000 | 52 | +1 | 1. b4 d5 2. f3 Nc6 3. b5 Na5 4. e4 b6 |
| S8 | 1 600 000 000 | 56 | 0 | 1. b4 d5 2. f3 Nc6 3. b5 Na5 4. e4 a6 |
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: 0
- Lc0 0.32.1: -3
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 +55, Black +58, difference -3. 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 | 0 | 42 | 1. b4 d5 2. e4 a5 3. b5 dxe4 4. f3 c6 5. a4 exf3 |
| 2 | -24 | 41 | 1. b3 d5 2. e4 b6 3. exd5 Qxd5 4. f4 c5 5. Qe3 Qd6 |
| 3 | -30 | 41 | 1. e4 g6 2. f4 b6 3. Qf2 c5 4. e5 d6 5. O-O dxe5 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 31 cp, mean 8.1 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | b4 | 0 | a5 | -4 |
| 2 | b5 | +30 | c6 | +21 |
| 3 | a4 | +18 | Qa7 | +14 |
| 4 | e4 | +23 | g6 | +25 |
| 5 | Bxh8 | +31 | Rxh8 | +15 |
| 6 | Nc3 | +20 | d6 | +27 |
| 7 | f4 | +24 | Qxg1+ | +25 |
| 8 | Rxg1 | +26 | h5 | +18 |
| 9 | Nb3 | +29 | b6 | +14 |
| 10 | Be2 | +12 | Bg4 | +7 |
| 11 | bxc6 | +14 | Nxc6 | +4 |
| 12 | Nd5 | 0 | Be6 | +9 |
| 13 | c3 | +6 | Nf6 | +1 |
| 14 | Nxf6 | +9 | Bxb3 | +5 |
| 15 | Nd5 | +7 | Bxa4 | +6 |
| 16 | Nxb6 | +5 | Bc2 | +4 |
| 17 | Bb5 | +3 | Na7 | +4 |
| 18 | Ba4 | +2 | Bxa4 | 0 |
| 19 | Nxa4 | 0 | Rb8 | +5 |
| 20 | Ke2 | +8 | Kg7 | +7 |
| 21 | Rb1 | 0 | Nc6 | 0 |
| 22 | d4 | 0 | e6 | 0 |
| 23 | Kd3 | 0 | Ne7 | 0 |
| 24 | g3 | +2 | h4 | 0 |
| 25 | Rgf1 | 0 | Rxb1 | 0 |
| 26 | Rxb1 | 0 | hxg3 | 0 |
| 27 | hxg3 | 0 | Rh3 | 0 |
| 28 | Rb7 | 0 | Rxg3+ | 0 |
| 29 | Ke2 | 0 | Rg2+ | 0 |
| 30 | Kd3 | 0 | Rg3+ | 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 42.2 moves.
Sample game 1 (1/2-1/2)
1. b3 d5 2. e4 b6 3. exd5 Qxd5 4. f4 Nc6 5. Qe3 Qd6 6. Bf3 Nb4 7. Na3 Nf6 8. Qe5 g6 9. Qxd6 cxd6 10. O-O Bf5 11. c3 Nd3 12. Nxd3 Bxd3 13. Be2 Bxe2 14. Rxe2 e6 15. c4 d5 16. d3 dxc4 17. dxc4 O-O 18. Nc2 Bg7 19. Ne1 h5 20. Nf3 Rd3 21. Rd2 Rxd2 22. Nxd2 Rd8 23. Nf3 Ne4 24. Re1 Bxa1 25. Rxa1 Nc3 26. Kf2 Rd3 27. Rc1 Nxa2 28. Ra1 Nb4 29. Rxa7 Rxb3 30. Ng5 e5 31. g3 Nd3+ 32. Ke3 Nc5+ 33. Ke2 Rb2+ 34. Ke3 Rb3+ 35. Ke2 Rb2+ 36. Ke3
Sample game 2 (1/2-1/2)
1. b3 d5 2. h4 c5 3. Qh2 Nc6 4. Nd3 b6 5. Ne5 g6 6. Nxc6 Qxc6 7. Bxh8 Rxh8 8. d3 c4 9. Qf4 h5 10. Qd4 Qf6 11. Qxf6 Nxf6 12. dxc4 dxc4 13. f3 Nd5 14. c3 Kg7 15. Kf2 b5 16. Bc2 e5 17. bxc4 bxc4 18. Na3 Ba6 19. Nb1 Rc8 20. Rd1 Rc5 21. e4 Nf4 22. Rd6 Ra5 23. a4 Rb8 24. Rhd1 Bc8 25. g3 Nd3+ 26. Bxd3 cxd3 27. Nd2 Rxa4 28. Rd8 Ra2 29. Ke3 a5 30. f4 Bg4 31. Rxb8 exf4+ 32. gxf4 Bxd1 33. Ra8 Be2 34. c4 a4 35. c5 a3 36. c6 Rc2 37. Rxa3 Rxc6 38. Ra1 Rc2 39. Nb3 Rc6 40. Nd2 Rc8
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 65 / 103 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): qnbrnkrb/pppppppp/8/8/8/8/PPPPPPPP/BNNBRKQR w EHdg - 0 1
Mirror twin: White 891 vs Black 850 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 287.