White 71 vs Black 98
White starts from setup 71 (NNBRKQRB), Black from setup 98 (BQNRNBKR). In the encyclopedia since 2026-10-15: 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. 71, Black by position No. 98, 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 #71 N N B R K Q R B
King on the e-file, rooks on d, g, queen on the f-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 71 gives White +0.37 (Morozov Balance Index, 400M nodes).
Black: setup #98 B Q N R N B K R
King on the g-file, rooks on d, h, queen on the b-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 98 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 59.
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 ±13 cp.
For comparison, in symmetric play setup 71 gives White +0.37 and setup 98 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 e4; the alternatives are slightly weaker but keep the game level.
Along the engine's main line (30 moves) the largest swing was 48 cp (around move 23), ending at +34 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 | 15 | -9 | 1. e4 h5 2. Qe2 b5 3. O-O c5 4. d3 e6 |
| S1 | 500 000 | 17 | -4 | 1. e4 c5 2. g3 h5 3. h4 d5 4. exd5 b5 |
| S2 | 2 000 000 | 22 | +9 | 1. e4 c5 2. g3 h5 3. Nb3 e6 4. d4 cxd4 |
| S3 | 8 000 000 | 31 | -5 | 1. e4 c5 2. g3 b5 3. Qe2 e6 4. d3 Ne7 |
| S4 | 32 000 000 | 37 | -13 | 1. e4 c5 2. g3 e6 3. Qe2 b5 4. d3 Ne7 |
| S5 | 128 000 000 | 40 | -6 | 1. e4 c5 2. g3 b5 3. Qe2 h5 4. h4 e6 |
| S6 | 400 000 000 | 50 | 0 | 1. e4 c5 2. g3 b5 3. Qe2 h5 4. h4 e6 |
| S7 | 800 000 000 | 52 | 0 | 1. e4 c5 2. g3 b5 3. Qe2 e6 4. d3 Ne7 |
| S8 | 1 600 000 000 | 59 | 0 | 1. e4 c5 2. g3 b5 3. Qe2 e6 4. d3 Ne7 |
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: -14
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 +78, Black +110, difference -32. 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 | -7 | 42 | 1. e4 c5 2. g3 e6 3. Qe2 b5 4. d3 Ne7 5. O-O h5 |
| 2 | -20 | 41 | 1. g3 d5 2. Nb3 b6 3. d3 g6 4. e4 dxe4 5. Bxe4 Bg7 |
| 3 | -33 | 41 | 1. d3 d5 2. g3 b5 3. e4 dxe4 4. Bxe4 Bxe4 5. dxe4 Rxd1+ |
Main-line play-out
30 moves, 5 000 000 nodes per half-move. Largest |evaluation| 48 cp, mean 17.5 cp, final +34 cp.
| # | White | cp | Black | cp |
|---|---|---|---|---|
| 1 | e4 | -5 | c5 | -3 |
| 2 | g3 | -3 | e6 | 0 |
| 3 | Qe2 | -1 | b5 | -3 |
| 4 | d3 | -6 | Be7 | -10 |
| 5 | O-O | -3 | O-O | -5 |
| 6 | Rfe1 | 0 | Nf6 | -8 |
| 7 | Nb3 | -12 | d6 | -16 |
| 8 | c3 | -16 | Nb6 | -17 |
| 9 | Na3 | -12 | Nbd7 | -16 |
| 10 | Bg2 | -16 | Rfe8 | -25 |
| 11 | d4 | -21 | a6 | -32 |
| 12 | f3 | -25 | Qc7 | -23 |
| 13 | Be3 | -14 | Bf8 | -28 |
| 14 | Bf2 | -9 | c4 | -21 |
| 15 | Nc1 | -20 | h5 | -17 |
| 16 | Nc2 | -24 | Nb6 | -28 |
| 17 | Qd2 | -24 | Bc6 | -22 |
| 18 | h3 | -23 | a5 | -27 |
| 19 | g4 | -29 | hxg4 | -28 |
| 20 | hxg4 | -39 | e5 | -42 |
| 21 | d5 | -41 | Bd7 | -36 |
| 22 | Ne2 | -41 | Be7 | -27 |
| 23 | Be3 | -48 | Nh7 | -44 |
| 24 | Kh2 | -35 | Na4 | -26 |
| 25 | Rh1 | -5 | Nxb2 | 0 |
| 26 | Rb1 | 0 | Nd3 | 0 |
| 27 | Bf1 | 0 | Rb8 | 0 |
| 28 | Kg1 | 0 | f6 | 0 |
| 29 | Ng3 | 0 | Ng5 | +4 |
| 30 | Kg2 | +37 | b4 | +34 |
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 42.0 moves.
Sample game 1 (1/2-1/2)
1. e4 e6 2. g3 c5 3. Qe2 b5 4. d3 h5 5. h4 Nf6 6. Bf4 Qb6 7. O-O Ng4 8. c3 d5 9. exd5 exd5 10. Nc2 Bd6 11. Bg5 f6 12. Bc1 O-O 13. Rde1 Qc7 14. d4 Rde8 15. Qd3 c4 16. Qf5 Qf7 17. Rxe8 Rxe8 18. Re1 Nb6 19. Rxe8+ Qxe8 20. Nd2 Bc6 21. Qf3 a5 22. Nf1 Qe4 23. Nce3 Nxe3 24. Nxe3 Qb1 25. Qd1 g6 26. Bf3 Kf7 27. g4 hxg4 28. Nxg4 Qd3 29. Qxd3 cxd3 30. b3 f5 31. Ne3 b4 32. Bd2 bxc3 33. Bxc3 a4 34. Kf1 Ke6 35. h5 gxh5 36. Bxh5 Bf4 37. Ng2 Bd6 38. Ne3 Bf4 39. Ng2 Bd6
Sample game 2 (1/2-1/2)
1. e4 e6 2. Qe2 c5 3. g3 b5 4. d3 Ne7 5. h4 h5 6. c3 Nf6 7. Nd2 Ng6 8. Nc2 d5 9. O-O Be7 10. exd5 exd5 11. d4 O-O 12. Rfe1 Rde8 13. Nf1 cxd4 14. Nxd4 b4 15. Bg5 bxc3 16. bxc3 Bc5 17. Ne3 Ne4 18. Bxe4 Rxe4 19. Qxh5 Rfe8 20. Qe2 Qb6 21. h5 Ne5 22. Bf4 Nc6 23. Ndf5 Ne7 24. Nd4 Bxd4 25. Rxd4 Rxd4 26. cxd4 Nc6 27. Rd1 Nxd4 28. Qg4 Ne2+ 29. Qxe2 d4 30. Kh2 dxe3 31. g4 Bb7 32. fxe3 Rd8 33. Rxd8+ Qxd8 34. Kg3 Qd5 35. e4 Qc5 36. Qe3 Qc2 37. h6 Bxe4 38. Qd2 Qxd2 39. Bxd2 gxh6 40. Bxh6 Kh7
Play it in the CH960 app
Open this page on a phone with the CH960 app installed, or find pair 71 / 98 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): bqnrnbkr/pppppppp/8/8/8/8/PPPPPPPP/NNBRKQRB w DGdh - 0 1
Mirror twin: White 882 vs Black 855 — a different position (castling squares are fixed), not evaluated by the search.
Current place in the live balance rating: 311.