Dive into our comprehensive ECO codes section, featuring the full A00-E99 system from the Encyclopaedia of Chess Openings. Discover opening families, sub-variations, and stats—ideal for players sorting databases, studying plans, or finding games. From Queen’s Gambit (D20s) to Najdorf (B90), enhance your prep with precise classifications and expert insights.

A00 A03 A06 A15 A41 A48 A65 B00 B01 B07 B13 B20 B40 B50 B54 B57 B92 C01 C07 C11 C40 C44 C46 C48 D02 D03 D10 D15 D31 D35 D36 D37 D38 D43 D85 E00 E10 E12 E32 E39 E46 E81 E92

A: Flank Openings

Volume A covers irregular starts, flank attacks, and sidelines like 1.c4 or 1.Nf3. Key families include English Opening (A10-A39, 1.c4), Réti (A04-A09, 1.Nf3), Bird’s (A02-A03, 1.f4), and Nimzowitsch-Larsen (A01, 1.b3). Dutch Defense (A80-A99, 1.d4 f5) and Benoni (A50-A79) add dynamic counterplay.​

B: Semi-Open Games

B focuses on Black’s asymmetric replies to 1.e4, like Sicilians and Caro-Kann. Sicilian dominates with Najdorf (B90-B99, …a6), Dragon (B70-B79, …g6), and Taimanov (B40-B49, …e6). Others: Alekhine (B00-B05, 1.e4 Nf6?), Pirc/Modern (B06-B09), Caro-Kann (B10-B19, 1.e4 c6).​

C: Open Games and French

C includes 1.e4 e5 (double king pawn) plus French Defense. Ruy Lopez (C60-C99, 3.Bb5) leads, followed by Italian (C50-C59, 3.Bc4), Scotch (C44-C45, 3.d4), Petrov (C42-C43), and King’s Gambit (C30-C39, 2.f4). French starts with C00-C19 (1.e4 e6).​

D: Closed Queen’s Pawn Games

D handles 1.d4 d5 structures, Queen’s Gambit, and Grünfeld. Queen’s Gambit Declined (D30-D69) is core, with Slav (D10-D19, …c6), Accepted (D20-D29, …dxc4), and early systems (D00-D09 like London). Grünfeld (D80-D99, …g6) brings hypermodern tension.​

E: Indian Defenses

E features …Nf6 setups with …e6 or …g6, like Nimzo-Indian and King’s Indian. Nimzo (E20-E59, 3.Nc3 Bb4) splits into Sämisch and Classical; Queen’s Indian (E12-E19, …b6); Catalan (E01-E09). Early branches in E00-E11 transition flexibly

A00 A03 A06 A15 A41 A48 A65 B00 B01 B07 B13 B20 B40 B50 B54 B57 B92 C01 C07 C11 C40 C44 C46 C48 D02 D03 D10 D15 D31 D35 D36 D37 D38 D43 D85 E00 E10 E12 E32 E39 E46 E81 E92