: Puzzles are grouped into 5 main folders (A through E) and subdivided into 495 specific PGN files by ECO code.
: These are designed for offline training or for use in external chess software (like Scid vs. PC) where users want to drill tactics that arise from their own opening repertoire. Where to Find the Data Lichess Puzzles By Eco zip
These zip files are typically PGN (Portable Game Notation) collections structured so you can practice tactics specifically related to certain openings: : Puzzles are grouped into 5 main folders
While the official Lichess database provides puzzles in a single large CSV or BZ2 file, the "By ECO" organization was a specific project shared by community members: download all puzzles - Lichess.org Where to Find the Data These zip files
The phrase refers to a popular community-curated dataset where millions of Lichess puzzles are organized into zip files based on their Encyclopedia of Chess Openings (ECO) codes . What the Zip Files Contain
: Each puzzle entry includes the starting FEN, the move sequence to solve it, the puzzle's rating, and "Themes" tags (e.g., fork, pin, mate in 2).