Chess Engines Ratings Lists: IJCCRL Arena Series 2026 Classical Provisional Update for the Original UCI Track
The IJCCRL Arena Series 2026 — Classical — Original UCI Track — League Stage remains in progress. This post records the audited provisional Classical rating surface after 140 completed games from the planned 180-game round robin, including the current Elo base 3500 table, colour-balance state, and the treatment of three technical interruption records.
In discussions about chess engines ratings lists, provisional data must be handled with explicit limits. A current rating surface can be useful before a league is complete, but only if the sample size, tournament structure, colour balance, rating base, and incident treatment are stated clearly. This IJCCRL Classical update is therefore published as an audited provisional object, not as a final rating list. The current state contains 140 completed games from a scheduled 180-game round robin. Each engine has completed 28 games, with exact colour symmetry at 14 White and 14 Black games.
Audit conclusion
- Audit status: audited provisional.
- Current games: 140 / 180.
- Completion: 77.78%.
- Engines: 10.
- Games per engine: 28.
- Colour balance: 14 White / 14 Black per engine.
- Opening system: fixed mirrored opening round robin, pair ratio 0.
- Rating scale: Elo base 3500.
Technical incident treatment
Three proxy_fatal / readyok-timeout records at opening indices 75, 76 and 77 were reviewed as technical interruptions rather than normal sporting losses. The affected games stopped at the 16-ply UHO opening line, with no terminal result, no tablebase evidence, and no decisive material evidence. For this rating surface, those three games are therefore counted as 1/2-1/2, while the raw records remain preserved.
Provisional Classical rating table
The following table records the current IJCCRL Classical rating surface for the Original UCI Track. The list is ordered by provisional Elo on the base 3500 scale. It should be read as an in-progress rating object, not as the final league result.
| # | Engine | Elo | Pts | GP | W-D-L | Score % | League note |
|---|---|---|---|---|---|---|---|
| 1 | Stockfish 18 Current provisional leader | 3619 | 18.5 | 28 | 13-11-4 | 66.07% | Current leader |
| 2 | Obsidian 16.0 Half-point behind the leader | 3600 | 18.0 | 28 | 11-14-3 | 64.29% | Second place |
| 3 | Reckless 0.10.0-dev-6abcff05 | 3559 | 16.0 | 28 | 9-14-5 | 57.14% | Upper group |
| 4 | PlentyChess 7.0.55 | 3507 | 15.0 | 28 | 10-10-8 | 53.57% | Upper-midfield |
| 5 | Dragon 3.3 by Komodo Chess 64-bit | 3490 | 13.5 | 28 | 8-11-9 | 48.21% | Midfield |
| 6 | Berserk 13 | 3489 | 13.0 | 28 | 7-12-9 | 46.43% | Midfield |
| 7 | Caissa 1.24 AVX2 | 3480 | 13.5 | 28 | 7-13-8 | 48.21% | Midfield |
| 8 | Clover 9.1 | 3467 | 12.5 | 28 | 6-13-9 | 44.64% | Lower-midfield |
| 9 | RubiChess 20240817 (avx2) | 3415 | 11.0 | 28 | 4-14-10 | 39.29% | Lower group |
| 10 | Integral v7.0.0 | 3374 | 9.0 | 28 | 3-12-13 | 32.14% | Tenth place |
Current leader profile
Stockfish 18 is the current provisional leader with 18.5/28 and an Elo estimate of 3619 on the base 3500 scale. The lead is narrow rather than closed: Obsidian 16.0 stands second with 18.0/28, only half a point behind. This is why the present table should not be described as final. It is a current Classical rating surface from a tournament that still has 40 games remaining.
The strongest current head-to-head segment for Stockfish 18 is against Reckless 0.10.0-dev-6abcff05, where it has scored 3.0/4. Stockfish has also scored 2.5/4 against Berserk 13, Caissa 1.24 AVX2, Dragon 3.3 by Komodo Chess 64-bit, and Obsidian 16.0. Against Integral v7.0.0, the two affected timeout records were adjudicated as draws for rating purposes, leaving that current segment at 1.0/2.
Leader-vs-field chart slots
The following image slots are intended for supporting charts comparing Stockfish 18 with the rest of the Original UCI field. Upload the prepared chart images to the WordPress Media Library and replace the image URLs below.
For readers following chess engines ratings lists with a methodological focus, this publication should be interpreted as a provisional audit surface. It is tied to a stated tournament design, exact colour symmetry at the current 28-game-per-engine state, Elo base 3500, and explicit handling of three technical interruptions. Final publication requires the complete 180-game round robin.