Chess openings and defenses: ECO catalogue

Find openings, defenses and variations by name and ECO code. Read the moves, download PGN lines and open them on the AiChess board.

Choose a volume, then an ECO code: each entry provides the original variation name and the complete available sequence. Use your browser’s Find command to search by name. The code classifies a family of positions, not the strength of a line.

3815 lines · 500 ECO codes · 149 families · 3815 distinct final positions

families

These sequences describe named positions in the Lichess catalogue. Their length varies: they are not complete courses or promises of an advantage. After the final move, Study lets you explore continuations calculated by Stockfish. No advice is available during games.