Lichess upgrades all artificial intelligence servers to the best chess engine in the world!

This week, something wonderful happened. Stockfish, the favorite open source competitor in the race for the best chess engine, has won the TCEC tournament.

Here are the chess engines ratings at the end of the tournament:

Stockfish 3168 Komodo 3151 Houdini 3145 Vitruvius 3098 Bouquet 3077 Rybka 3072

During the final event, after playing 64 games against Komodo, Stockfish won with the score of 35½ - 28½. No doubt is further allowed: Stockfish is the best chess player ever!

Challenge Stockfish on lichess

At lichess.org, we use Stockfish as the artificial intelligence, allowing players to play against the computer.

Ever wondered what the levels 1 to 8 mean? Levels have a direct effect on the Stockfish skill setting, the search depth, as well as the time it has to think about a move.

AI level 1: skill 3/20, depth 1, 50ms

AI level 2: skill 6/20, depth 2, 100ms

AI level 3: skill 9/20, depth 3, 150ms

AI level 4: skill 11/20, depth 4, 200ms

AI level 5: skill 14/20, depth 6, 250ms

AI level 6: skill 17/20, depth 8, 300ms

AI level 7: skill 20/20, depth 10, 350ms

AI level 8: skill 20/20, depth 12, 400ms

So when you're playing AI level 3, you're playing a stockfish that has only 0,15 seconds to make a decision, with artificially reduced skill.

Get Stockfish to analyse your games

A unique feature of lichess.org is computer analysis. You can ask Stockfish to run a deep analysis of any game: it's free, and there is no limitation on how many analyses you can request.

This example comes from a real game.

Not only does the analysis provide an advantage chart—it also highlights the errors players made during the game, and proposes alternative variations.

During an analysis, the full power of Stockfish is unleashed, at the speed of 2 seconds per move. Hopefuly, this work is distributed across all lichess servers, so the results of the analysis comes back to you really fast!

On the edge of chess software

Lichess uses the latest technologies to provide players with a great, fast and reliable experience. All our artificial intelligence servers now run Stockfish 5 - the new version that just won the TCEC tournament.

Now go and get your games analysed by the strongest chess player in the known universe! Stockfiiiiishhhhh… 5!

By the way, did you know you can paste games played outside of lichess, and get them analysed on lichess as well?