Dataset Card for Lichess Puzzles

Dataset Description

5,423,662 chess puzzles, rated and tagged. See them in action on Lichess.

This dataset is updated monthly, and was last updated on October 7th, 2025.

Dataset Creation

Generating the initial dataset chess puzzles took more than 50 years of CPU time. We went through 300,000,000 analyzed games from the Lichess database, and re-analyzed interesting positions with Stockfish 12/13/14/15 NNUE at 40 meganodes. The resulting puzzles were then automatically tagged. To determine the rating, each attempt to solve is considered as a Glicko-2 rated game between the player and the puzzle. Finally, player votes refine the tags and define popularity.