About AxiomChess

How the analysis works

The engine is Stockfish 18. Game review runs on our server with the full-strength Stockfish 18 network at depth 18. Turn Fast analysis off in Settings and it runs in your browser with the lighter engine at depth 20. The two engines are not identical: the server’s full network catches more errors in our testing, so a game can grade slightly differently in the browser. Every move in a game is graded on both sides of the board, with the engine’s lines kept visible so you can check the verdict yourself. There is no daily review limit, no account requirement, and no premium tier that unlocks a deeper search.

What the coach is, and is not

The coaching is deterministic. Each piece of advice comes from a stated chess principle, checked against the engine before it is allowed to speak, so the same game always gets the same review. There is no language model deciding what is true about your play. The personas change the emphasis and the voice, never the judgement.

Where the puzzles and openings come from

Nothing here is hand-invented. The puzzles are drawn from the Lichess puzzle database, released under the CC0 licence, and matched to the weaknesses your own games show. The opening lines are sourced from master practice through the Lichess opening explorer and checked move by move against Stockfish before they are taught. The AxiomChess opening trainer teaches those theoretical main lines and drills them with spaced repetition. For each position it shows what opponents at your Lichess rating band actually play and how to punish their common mistakes. The reply tables and the numbers on which openings punish mistakes come from Lichess games split by rating band; each opening page shows the tables behind its own figures.

Who builds it

Joshua Seiler builds AxiomChess. He is a club player, not a titled one, and the site started as the tool he wanted for his own games: honest grading, no upsell, and coaching that could show its reasoning. He also writes the blog, where every number comes from a reproducible measurement. He reviews and fact-checks every post before it is published, and answers for what it says.

Independence and contact

AxiomChess is not affiliated with Chess.com, Lichess, or the Stockfish project. Game data is fetched from the public APIs of the platform you name, and the analysis of it is stored on your device. Questions, corrections, and legal notices go to support@axiomchess.com. The privacy policy spells out exactly what the site does and does not collect.