Chess opening families, A–Z
The Encyclopaedia of Chess Openings (ECO) classifies every recognized opening into 500 codes across 5 volumes (A–E). This site tracks 3,810 named lines across 149 opening families; 64 families with 8 or more named lines have their own guide (linked below).
Or search and play all 3,810 lines in the interactive ECO explorer →
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Volume A: Flank Openings · Volume B: Semi-Open Games (other than the French Defense) · Volume C: Open Games and the French Defense · Volume D: Closed Games and Semi-Closed Games · Volume E: Indian Defenses
Families Alekhine Defense–Lasker Simul Special
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| Family | ECO codes | Lines |
|---|---|---|
| Alekhine Defense | B02–B05 | 56 |
| Amar Opening | A00 | 3 |
| Amazon Attack | A45–D00 | 2 |
| Amsterdam Attack | A00 | 1 |
| Anderssen's Opening | A00 | 2 |
| Australian Defense | A40 | 1 |
| Barnes Defense | B00 | 1 |
| Barnes Opening | A00–C20 | 6 |
| Basque Opening | A45 | 1 |
| Benko Gambit | A57–A59 | 8 |
| Benko Gambit Accepted | A57–A59 | 10 |
| Benko Gambit Declined | A57 | 6 |
| Benoni Defense | A40–A79 | 61 |
| Bird Opening | A02–B21 | 28 |
| Bishop's Opening | C23–C43 | 41 |
| Blackmar-Diemer Gambit | D00 | 18 |
| Blackmar-Diemer Gambit Accepted | D00 | 22 |
| Blackmar-Diemer Gambit Declined | D00 | 9 |
| Blumenfeld Countergambit | E10 | 3 |
| Blumenfeld Countergambit Accepted | E10 | 1 |
| Bogo-Indian Defense | E11 | 21 |
| Bongcloud Attack | C20 | 1 |
| Borg Defense | A40–B00 | 5 |
| Canard Opening | A45 | 1 |
| Caro-Kann Defense | B10–B19 | 110 |
| Carr Defense | B00 | 2 |
| Catalan Opening | E00–E09 | 32 |
| Center Game | C20–C22 | 18 |
| Center Game Accepted | C21 | 1 |
| Clemenz Opening | A00 | 2 |
| Colle System | A04–A40 | 3 |
| Creepy Crawly Formation | A00 | 1 |
| Czech Defense | B07 | 1 |
| Danish Gambit | C21 | 1 |
| Danish Gambit Accepted | C21 | 6 |
| Danish Gambit Declined | C21 | 1 |
| Döry Defense | A46 | 1 |
| Dresden Opening | C44 | 1 |
| Duras Gambit | B00 | 1 |
| Dutch Defense | A80–A99 | 69 |
| East Indian Defense | A48 | 1 |
| Elephant Gambit | C40 | 4 |
| English Defense | A40 | 7 |
| English Opening | A10–C20 | 175 |
| English Orangutan | A15 | 2 |
| Englund Gambit | A40 | 9 |
| Englund Gambit Declined | A40 | 7 |
| Formation | A00 | 2 |
| Four Knights Game | C47–C50 | 49 |
| French Defense | C00–C19 | 212 |
| Fried Fox Defense | B00 | 1 |
| Global Opening | A00 | 1 |
| Goldsmith Defense | B00 | 2 |
| Grob Opening | A00 | 20 |
| Grünfeld Defense | A56–E60 | 59 |
| Gunderam Defense | C40 | 1 |
| Hippopotamus Defense | B00 | 2 |
| Horwitz Defense | A40 | 2 |
| Hungarian Opening | A00–A07 | 20 |
| Indian Defense | A43–E60 | 53 |
| Irish Gambit | C44 | 1 |
| Italian Game | C50–C59 | 187 |
| Kádas Opening | A00 | 9 |
| Kangaroo Defense | A40 | 2 |
| King's Gambit | C30 | 1 |
| King's Gambit Accepted | C33–C39 | 137 |
| King's Gambit Declined | C30–C32 | 53 |
| King's Indian Attack | A05–A08 | 20 |
| King's Indian Attack, with Bf5 | A07 | 5 |
| King's Indian Attack, with e6 | A07 | 2 |
| King's Indian Defense | E60–E99 | 119 |
| King's Knight Opening | C40–C44 | 3 |
| King's Pawn Game | B00–C44 | 38 |
| King's Pawn Opening | C20 | 3 |
| Lasker Simul Special | A00 | 1 |