Chess engines rating list

Chess Engines Rating List — Participants & Context

This page lists the engines that actively compete in IJCCRL rating events (Blitz and Bullet divisions). All runs are reproducible: identical hardware, Threads=1, Hash=16, Syzygy 5-man, fixed UHO 8-move openings, and round-robin schedules via CuteChess-CLI. Ratings are computed with BayesElo and cross-checked with Ordo (we never mix time controls or hardware between lists).

Below you’ll find only the engines present in our current tournament command files.

Engines in our lists (alphabetical)

Alexandria (8.1.0) — open-source UCI engine; bitboard design; actively maintained by the author under the handle PGG106. (GitHub)

Berserk — original NNUE engine by Jay Honnold (C, GPLv3). Early versions used HCE; modern releases use an in-house NNUE. (Chessprogramming)

Caissa — original UCI engine by Michal Witanowski; open-source and fast-moving project (see the author’s TalkChess intro). (TalkChess)

Clover (9.0-old) — open-source UCI engine by Luca (Luc) Metehau; switched from handcrafted eval to NNUE from v3.x onward. (Chessprogramming, chessengeria.eu, Computer Chess Rating Lists)

Dragon (Komodo Dragon 3.3) — NNUE engine from the Komodo team (GM Larry Kaufman & Mark Lefler; legacy work by Don Dailey). (Chessprogramming)

Ethereal (14.25) — original engine by Andrew Grant (also author of OpenBench); strong alpha-beta + NNUE setup. (Chessprogramming, GitHub)

Integral (SSE4.1+POPCNT build) — original NNUE engine by Aron Petkovski (active upstream on GitHub). (Chessprogramming, GitHub)

Obsidian (16.14) — top-tier open-source engine by Gabriele Lombardo (aka gab8192). (GitHub, Chessdom)

RubiChess (20240817) — open-source engine by Andreas Matthies; long-running project with NNUE support since 2020. (Chessprogramming, Chessify)

Seer (2.8) — original NNUE engine by Connor McMonigle; custom training pipeline and inference code. (Chessprogramming, GitHub)

Stockfish (17.1) — community-developed open-source engine (originated by Tord Romstad, Marco Costalba, Joona Kiiski; now maintained by a large team). (Stockfish, Wikipedia)

Stormphrax (7.0.0) — C++ NNUE engine by Ciekce (credited as Conor Anstey in event rosters). (GitHub, wiki.chessdom.org)

Titan (x64) — modern UCI engine with public builds and testing on CCRL; upstream credits point to the jeff-pow/Titan repository (community JA builds also circulate). (computerchess.org.uk, TalkChess)

Velvet (8.1.1) — open-source engine written in Rust by Martin Honert; NNUE since 2.0; active multi-arch releases. (Chessprogramming, GitHub)

How to read our lists

• Separate divisions: Bullet and Blitz results are published independently; no cross-mixing of time controls.
• Fairness constraints: identical hardware, 1-thread, small hash, same UHO openings & Syzygy depth.
• Ratings: primary BayesElo with error bars; Ordo as an independent cross-check.