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.
Frequency in master games, from Lichess Masters DB.
Win % for White, ≥ 1,500 master games.
Win % for Black, ≥ 1,500 master games.
Every family in the encyclopaedia, and under each one the variations that carry their own study — editorial coverage, or enough master practice for the statistics to mean something. Families link through to the full tree, which continues past what is listed here.
Flank openings and irregular
Semi-open games, Sicilian
1.e4 e5 and the French
Closed games, Queen's Gambit
Indian defences
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. Caissly carries all 3,161 named lines — each with an interactive playable board, the canonical PGN and its parent, sibling and child variations — and studies 461 of them in their own right. The remainder are waypoints in the tree rather than destinations: walk into them from any family above, or open the Explorer to move through the whole encyclopaedia position by position.