Highest White scoring
Win % for White, ≥ 1,500 master games.
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 Sicilian Defense
- 2 Sicilian Defense: Modern Variations
- 3 Queen's Gambit
- 4 English Opening
- 5 Ruy Lopez
- 6 French Defense
- 7 Indian Defense: Anti-Nimzo-Indian
- 8 Indian Defense: West Indian Defense
- 9 Sicilian Defense: Old Sicilian
- 10 Sicilian Defense: Najdorf Variation
- 11 King's Indian Defense
- 12 Ruy Lopez: Morphy Defense
Highest Black scoring
Win % for Black, ≥ 1,500 master games.
Browse by ECO volume
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.
A
Volume A
Flank openings and irregular
70 families · 672 lines carried
- ECO A40 Queen's Pawn Game 48 lines
- ECO A45 Indian Defense 50 lines
- ECO A04 Zukertort Opening 41 lines
- ECO A10 English Opening 126 lines
- ECO A48 East Indian Defense 1 line
- ECO A40 Horwitz Defense 2 lines
- ECO A56 Benoni Defense 47 lines
- ECO A80 Dutch Defense 57 lines
- ECO A05 King's Indian Attack 12 lines
- ECO A45 Trompowsky Attack 9 lines
- ECO A00 Hungarian Opening 20 lines
- ECO A09 Réti Opening 20 lines
- ECO A57 Benko Gambit 7 lines
- ECO A57 Benko Gambit Accepted 9 lines
- ECO A01 Nimzo-Larsen Attack 13 lines
- ECO A07 King's Indian Attack, with e6 1 line
- ECO A46 Yusupov-Rubinstein System 1 line
- ECO A46 Torre Attack 6 lines
- ECO A02 Bird Opening 27 lines
- ECO A41 Old Indian Defense 13 lines
- ECO A48 London System 2 lines
- ECO A41 Wade Defense 1 line
- ECO A41 Modern Defense 37 lines
- ECO A50 Slav Indian 2 lines
- ECO A00 Van Geet Opening 33 lines
- ECO A40 Kangaroo Defense 2 lines
- ECO A47 Pseudo Queen's Indian Defense 1 line
- ECO A07 King's Indian Attack, with Bf5 1 line
- ECO A00 Polish Opening 24 lines
- ECO A50 Mexican Defense 2 lines
- ECO A50 Queen's Indian Accelerated 1 line
- ECO A40 Mikenas Defense 4 lines
- ECO A40 English Defense 6 lines
- ECO A00 Van't Kruijs Opening 5 lines
- ECO A00 Anderssen's Opening 2 lines
- ECO A00 Mieses Opening 4 lines
- ECO A40 Polish Defense 2 lines
- ECO A41 Robatsch Defense 1 line
- ECO A48 London System, with Be2 1 line
- ECO A00 Polish Opening, with d5 1 line
- ECO A00 Saragossa Opening 1 line
- ECO A47 Marienbad System 2 lines
- ECO A42 Pterodactyl Defense 34 lines
- ECO A00 Grob Opening 20 lines
- ECO A00 Clemenz Opening 2 lines
- ECO A56 Vulture Defense 1 line
- ECO A40 Englund Gambit 9 lines
- ECO A45 Paleface Attack 1 line
- ECO A57 Benko Gambit Declined 6 lines
- ECO A00 Kádas Opening 7 lines
- ECO A40 Australian Defense 1 line
- ECO A04 Colle System 3 lines
- ECO A00 Amar Opening 3 lines
- ECO A00 Ware Opening 7 lines
- ECO A45 Canard Opening 1 line
- ECO A00 Lasker Simul Special 1 line
- ECO A00 Creepy Crawly Formation 1 line
- ECO A40 Montevideo Defense 1 line
- ECO A00 Sodium Attack 4 lines
- ECO A00 Global Opening 1 line
- ECO A46 Döry Defense 1 line
- ECO A48 London System, with Bd3 1 line
- ECO A00 Barnes Opening 5 lines
- ECO A15 English Orangutan 1 line
- ECO A00 Valencia Opening 1 line
- ECO A40 Englund Gambit Declined 7 lines
- ECO A04 Zukertort Defense 2 lines
- ECO A00 Amsterdam Attack 1 line
- ECO A00 Formation 2 lines
- ECO A40 Zaire Defense 1 line
B
Volume B
Semi-open games, Sicilian
21 families · 674 lines carried
- ECO B00 King's Pawn Game 35 lines
- ECO B20 Sicilian Defense 327 lines
- ECO B10 Caro-Kann Defense 92 lines
- ECO B00 Pirc Defense 23 lines
- ECO B01 Scandinavian Defense 42 lines
- ECO B02 Alekhine Defense 53 lines
- ECO B00 Nimzowitsch Defense 41 lines
- ECO B07 Czech Defense 1 line
- ECO B07 Lion Defense 6 lines
- ECO B00 Owen Defense 8 lines
- ECO B00 St. George Defense 4 lines
- ECO B00 Rat Defense 11 lines
- ECO B00 Borg Defense 4 lines
- ECO B00 Carr Defense 2 lines
- ECO B00 Lemming Defense 1 line
- ECO B00 Goldsmith Defense 2 lines
- ECO B00 Hippopotamus Defense 1 line
- ECO B00 Barnes Defense 1 line
- ECO B00 Duras Gambit 1 line
- ECO B00 Ware Defense 2 lines
- ECO B00 Fried Fox Defense 1 line
C
Volume C
1.e4 e5 and the French
30 families · 1089 lines carried
- ECO C40 King's Knight Opening 3 lines
- ECO C60 Ruy Lopez 200 lines
- ECO C00 French Defense 170 lines
- ECO C50 Italian Game 156 lines
- ECO C42 Petrov's Defense 42 lines
- ECO C44 Scotch Game 48 lines
- ECO C47 Four Knights Game 39 lines
- ECO C46 Three Knights Opening 5 lines
- ECO C23 Bishop's Opening 40 lines
- ECO C25 Vienna Game 40 lines
- ECO C41 Philidor Defense 38 lines
- ECO C30 King's Gambit 1 line
- ECO C33 King's Gambit Accepted 128 lines
- ECO C20 Center Game 15 lines
- ECO C21 Center Game Accepted 1 line
- ECO C44 Ponziani Opening 13 lines
- ECO C30 King's Gambit Declined 50 lines
- ECO C40 Latvian Gambit 17 lines
- ECO C25 Vienna Gambit, with Max Lange Defense 15 lines
- ECO C40 Gunderam Defense 1 line
- ECO C40 Elephant Gambit 4 lines
- ECO C21 Danish Gambit 1 line
- ECO C21 Danish Gambit Declined 1 line
- ECO C20 Portuguese Opening 3 lines
- ECO C21 Danish Gambit Accepted 6 lines
- ECO C40 Latvian Gambit Accepted 9 lines
- ECO C20 King's Pawn Opening 3 lines
- ECO C44 Irish Gambit 1 line
- ECO C20 Bongcloud Attack 1 line
- ECO C44 Dresden Opening 1 line
D
Volume D
Closed games, Queen's Gambit
17 families · 458 lines carried
- ECO D06 Queen's Gambit 1 line
- ECO D10 Slav Defense 43 lines
- ECO D30 Queen's Gambit Declined 137 lines
- ECO D43 Semi-Slav Defense 48 lines
- ECO D80 Grünfeld Defense 51 lines
- ECO D20 Queen's Gambit Accepted 47 lines
- ECO D32 Tarrasch Defense 26 lines
- ECO D44 Semi-Slav Defense Accepted 1 line
- ECO D01 Richter-Veresov Attack 7 lines
- ECO D01 Rapport-Jobava System 1 line
- ECO D05 Rubinstein Opening 4 lines
- ECO D70 Neo-Grünfeld Defense 10 lines
- ECO D00 Blackmar-Diemer Gambit 17 lines
- ECO D00 Blackmar-Diemer Gambit Accepted 21 lines
- ECO D01 Rapport-Jobava System, with e6 1 line
- ECO D00 Blackmar-Diemer Gambit Declined 8 lines
- ECO D00 Amazon Attack 2 lines
E
Volume E
Indian defences
10 families · 268 lines carried
- ECO E61 King's Indian Defense 109 lines
- ECO E20 Nimzo-Indian Defense 68 lines
- ECO E12 Queen's Indian Defense 48 lines
- ECO E00 Catalan Opening 14 lines
- ECO E11 Bogo-Indian Defense 10 lines
- ECO E10 Blumenfeld Countergambit 3 lines
- ECO E14 Queen's Indian Defense, with e3 1 line
- ECO E10 Blumenfeld Countergambit Accepted 1 line
- ECO E14 Queen's Indian Defense, with e3, Bb4+ Line 1 line
- ECO E60 Queen's Pawn, Mengarini Attack 1 line
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 87 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.