Sicilian Defence - ECO Codes

ECO Codes

The Encyclopaedia of Chess Openings classifies the Sicilian Defence under the codes B20 through B99, giving it more codes than any other opening. In general these guidelines apply:

• Codes B20 through B29 cover lines after 1.e4 c5 where White does not play 2.Nf3, and lines where White plays 2.Nf3 and Black responds with a move other than 2...d6, 2...Nc6 or 2...e6.
• Codes B30 through B39 cover the lines beginning 1.e4 c5 2.Nf3 Nc6 that do not transpose into lines that can also begin with 2...d6. The most important variations included here are the Rossolimo, Kalashnikov, Sveshnikov and Accelerated Dragon.
• Codes B40 through B49 cover the lines beginning 1.e4 c5 2.Nf3 e6, most importantly the Taimanov and Kan variations.
• Codes B50 through B59 cover the lines after 1.e4 c5 2.Nf3 d6 not covered in codes B60–B99. This includes the Moscow Variation (3.Bb5+), 3.d4 cxd4 4.Qxd4, and lines in the Classical Variation except for the Richter–Rauzer Attack, including the Sozin Attack and the Boleslavsky Variation.
• Codes B60 through B69 cover the Richter–Rauzer Attack of the Classical Variation.
• Codes B70 through B79 cover the normal (unaccelerated) Dragon Variation.
• Codes B80 through B89 cover the Scheveningen Variation.
• Codes B90 through B99 cover the Najdorf Variation.