White 61 vs Black 197
White starts from setup 61 (NNRBQKBR), Black from setup 197 (QNBBRKNR). In the encyclopedia since 2026-11-01: 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. 61, Black by position No. 197, 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 #61 N N R B Q K B R
King on the f-file, rooks on c, h, queen on the e-file; no 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 61 gives White +0.49 (Morozov Balance Index, 400M nodes).
Black: setup #197 Q N B B R K N R
King on the f-file, rooks on e, 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 197 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 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 same corridor is required at every deeper budget (8 G, 16 G) at which the pair has been evaluated.
The shallow rungs agreed early: from 100 thousand to 128 million nodes the evaluation never left ±14 cp.
For comparison, in symmetric play setup 61 gives White +0.49 and setup 197 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 f3; the alternatives are slightly weaker but keep the game level.
Along the engine's main line (30 moves) the evaluation stayed within ±17 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 | -5 | 1. f3 e5 2. e4 Nf6 3. c4 O-O 4. Be3 Nh5 |
| S1 | 500 000 | 22 | -5 | 1. f3 e5 2. c4 Ne7 3. Nc3 O-O 4. Bf2 b6 |
| S2 | 2 000 000 | 25 | -7 | 1. f3 e5 2. c4 Ne7 3. Nc3 O-O 4. Bf2 d6 |
| S3 | 8 000 000 | 30 | -8 | 1. f3 e5 2. c4 b6 3. Nc3 Nf6 4. e4 O-O |
| S4 | 32 000 000 | 37 | -14 | 1. f3 e5 2. c4 Ne7 3. Ba4 O-O 4. Nc3 a5 |
| S5 | 128 000 000 | 42 | -12 | 1. c4 e5 2. f3 Ne7 3. Nc3 O-O 4. Bf2 d6 |
| S6 | 400 000 000 | 46 | 0 | 1. c4 e5 2. f3 Nf6 3. e4 O-O 4. Nc3 Nh5 |
| S7 | 800 000 000 | 54 | 0 | 1. c4 e5 2. f3 Ne7 3. Ba4 O-O 4. Nc3 a5 |
| S8 | 1 600 000 000 | 54 | 0 | 1. c4 e5 2. f3 Ne7 3. Ba4 O-O 4. Nc3 a5 |
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: -5
- Lc0 0.32.1: +12
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 +38, Black +82, difference -44. 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 | -9 | 43 | 1. f3 e5 2. c4 Ne7 3. Ba4 O-O 4. Nc3 c6 5. d4 exd4 |
| 2 | -21 | 43 | 1. c4 e5 2. f3 Ne7 3. Ba4 O-O 4. Nc3 c6 5. d4 exd4 |
| 3 | -40 | 43 | 1. b4 e5 2. c4 b6 3. Nc3 Nf6 4. d3 d5 5. Ba4 Bd7 |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 17 cp, mean 4.3 cp, final 0 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | f3 | -13 | e5 | -17 |
| 2 | c4 | -11 | f5 | -17 |
| 3 | Nc2 | -4 | Nf6 | +6 |
| 4 | Nc3 | +13 | O-O | +5 |
| 5 | Bf2 | +4 | Nc6 | +7 |
| 6 | d4 | +14 | d6 | -1 |
| 7 | O-O | -1 | Qb8 | -8 |
| 8 | Kh1 | -6 | Ne7 | +7 |
| 9 | dxe5 | +9 | dxe5 | +6 |
| 10 | e4 | +9 | c6 | +4 |
| 11 | c5 | +6 | b5 | +6 |
| 12 | b4 | -1 | Kh8 | 0 |
| 13 | a4 | +12 | bxa4 | +9 |
| 14 | Bg1 | +1 | fxe4 | 0 |
| 15 | fxe4 | +7 | Ng6 | +10 |
| 16 | Ra1 | +10 | Be6 | +6 |
| 17 | Rxa4 | +9 | Nf4 | +4 |
| 18 | Ne3 | +2 | Nd3 | +3 |
| 19 | Qd2 | +4 | Nxb4 | +4 |
| 20 | Nf5 | 0 | Bxf5 | 0 |
| 21 | Rxf5 | 0 | a5 | 0 |
| 22 | Qe2 | 0 | Qb7 | 0 |
| 23 | Ra1 | 0 | Qa6 | 0 |
| 24 | Qb2 | 0 | Qa7 | 0 |
| 25 | Rf3 | 0 | Qe7 | 0 |
| 26 | Qe2 | 0 | Nd7 | 0 |
| 27 | Rh3 | 0 | Rf4 | 0 |
| 28 | Bb3 | 0 | h6 | 0 |
| 29 | Na4 | 0 | Nf6 | 0 |
| 30 | Re3 | 0 | Ng4 | 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 48.1 moves.
Sample game 1 (1/2-1/2)
1. f3 b6 2. c4 e5 3. Nc3 c5 4. Nc2 Re6 5. Ne3 Ne7 6. Bc2 Nbc6 7. Be4 O-O 8. Bf2 Bb7 9. O-O Rh6 10. Bh4 f6 11. Ncd5 Nd4 12. Nxe7+ Bxe7 13. Bxb7 Qxb7 14. Nd5 Bd6 15. e3 Nc6 16. e4 Nb4 17. Nxb4 cxb4 18. d3 f5 19. Bf2 Qc6 20. Kh1 Bc5 21. Rd1 Rd6 22. b3 a5 23. exf5 Rxf5 24. h3 Re6 25. Rd2 Rd6 26. Qd1 h6 27. d4 exd4 28. Bxd4 b5 29. Bxc5 Rxd2 30. Qxd2 Rxc5 31. cxb5 Rxb5 32. Rd1 d5 33. Qf4 Rc5 34. Rd2 Rc2 35. Rxc2 Qxc2 36. Qd6 Qd3 37. Qe6+ Kf8 38. Qc8+ Ke7 39. Qc7+ Kf6 40. Qd6+ Kf7
Sample game 2 (1/2-1/2)
1. c4 Nf6 2. d4 b6 3. f3 d5 4. cxd5 Nxd5 5. Ba4 c6 6. Bf2 O-O 7. O-O e5 8. Nc3 Nxc3 9. Qxc3 Bf6 10. Nc2 Bd7 11. dxe5 Bxe5 12. Qa3 c5 13. Bxd7 Nxd7 14. Rcd1 Rd8 15. e4 Nf6 16. b3 h5 17. Ne3 Bf4 18. h3 Qb8 19. Qb2 Qc7 20. Qc2 Rfe8 21. Rfe1 Bh2+ 22. Kf1 Bf4 23. Qc3 Be5 24. Qc1 Bf4 25. Qc3 Be5 26. Qc1 Bf4
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 61 / 197 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): qnbbrknr/pppppppp/8/8/8/8/PPPPPPPP/NNRBQKBR w CHeh - 0 1
Mirror twin: White 904 vs Black 666 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 263.