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What is Stockfish? The chess engine behind ChessMess

Stockfish is the strongest open-source chess engine. Learn how it works, how strong it is, and how ChessMess runs Stockfish 19 in your browser for free.

Updated · 1 min read

Stockfish is a free, open-source chess engine and one of the strongest chess programs ever made — far stronger than any human player.

How it works, briefly

Stockfish searches millions of positions per second, looking several moves ahead and pruning lines that can't matter. It scores positions with a neural network (NNUE) trained on huge numbers of positions. The result is an evaluation — who is better and by how much — and a best move.

How ChessMess uses Stockfish 19

ChessMess runs Stockfish 19 inside your browser using WebAssembly. That means:

Stockfish powers everything on ChessMess: the bots (which pick human-like moves from Stockfish's candidates), Coach mode, Game Review and the analysis board.

Can I play against full Stockfish?

Yes — pick Stockfish (3200) in Play a bot. Holding a draw is an achievement.

Credits

Stockfish is developed by the Stockfish team and released under the GPL-3.0 licence. See About for all the software ChessMess is built on.

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