The Library

Chess openings

Every Encyclopedia of Chess Openings classification — 3,161 lines from A00 to E99, with interactive playback and family hierarchy. Statistics from 2,808 positions tracked in master play.

Most played

Frequency in master games, from Lichess Masters DB.

  1. 1 King's Pawn Game B00 1,309,466 games
  2. 2 Queen's Pawn Game A40 1,029,878 games
  3. 3 Indian Defense A45 626,798 games
  4. 4 Sicilian Defense B20 601,092 games
  5. 5 Indian Defense: Normal Variation A50 456,632 games
  6. 6 Zukertort Opening A04 292,958 games
  7. 7 King's Knight Opening C40 289,898 games
  8. 8 King's Knight Opening: Normal Variation C44 249,218 games
  9. 9 Sicilian Defense: Modern Variations B50 231,200 games
  10. 10 Queen's Gambit D06 204,463 games
  11. 11 English Opening A10 199,442 games
  12. 12 Sicilian Defense: Modern Variations, Main Line B54 171,576 games

Browse by ECO volume

The Encyclopedia of Chess Openings divides theory into five volumes (A–E), each containing one hundred two-digit codes (00–99). Every code identifies a specific position reached by a defined move order. We carry every code; each page includes an interactive playable board, the canonical PGN, parent/sibling/child variations, and — for the most-studied lines — full editorial articles.