Asymmetric setups: balance rating
In an asymmetric game White starts from one of the 960 Chess960 back ranks and Black from another. Castling stays Chess960 castling for each side on its own rank. The search covers 460,800 of the 921,600 ordered pairs: one of each pair and its left–right mirror image. A mirror image is a different position, because castling always ends on the c/d or g/f files, so the other half of the space is not covered yet; a mirror twin's value is not an estimate of the pair's. This page ranks the pairs where the engine finds no starting edge for either side — including pairs where Black's rank fully compensates White's first move. This scheme is known as Double Fischer Random Chess (DFRC); engines have played it at TCEC since 2022.
CC BY 4.0 Methodology and data: CC BY 4.0 — free to use with attribution to the author.
Data generated 2026-09-23 05:11:31
How the search works
Every pair is first screened quickly; a pair moves to the next, deeper stage only while its evaluation stays inside a tightening window. Stages and windows (nodes per position, |cp| limit to advance): S0: 100 000 / ≤ 50; S1: 500 000 / ≤ 40; S2: 2 000 000 / ≤ 41; S3: 8 000 000 / ≤ 32; S4: 32 000 000 / ≤ 30; S5: 128 000 000 / ≤ 35. After the last stage the best 64 pairs keep receiving a doubled budget, without end. Single-thread search with a fixed node budget: every number is reproducible bit for bit.
Coverage so far
Explored 460 800 of 460 800 distinct pairs. The search never stops; this table is regenerated from the live data, and every explored pair is in the full download with its stage.
| Stage | Nodes | Pairs | Even (|cp| ≤ 10) | White better | Black better |
|---|---|---|---|---|---|
| S0 | 100 000 | 277 515 | 0 | 233961 | 43554 |
| S1 | 500 000 | 174 410 | 19204 | 97018 | 58188 |
| S2 | 2 000 000 | 1 599 | 0 | 872 | 727 |
| S3 | 8 000 000 | 693 | 0 | 405 | 288 |
| S4 | 32 000 000 | 491 | 0 | 268 | 223 |
| S5 | 128 000 000 | 5 487 | 1662 | 1958 | 1867 |
| S6 | ×2 | 485 | 344 | 60 | 81 |
| S7 | ×2 | 50 | 41 | 6 | 3 |
| S8 | ×2 | 70 | 67 | 2 | 1 |
Rating (verified pairs)
Only pairs that reached the verification stages (128 000 000 nodes and more) are ranked: closer to zero is higher; at equal evaluation the deeper one is higher. 5974 pairs verified, 1178 candidates in the pipeline.
Open data
Rating and coverage (JSON) and the full encyclopedia of every explored pair (CSV): white setup, black setup, mirror twin, stage, nodes, evaluation, depth, side, band, confidence, principal variation, FEN. CC BY 4.0, author Roman Morozov.
Morozov R. Asymmetric Chess960 balance rating. ch960.com/asym, 2026. CC BY 4.0.