Sicilian Defense: O'Kelly Variation, Normal System, Cortlever Gambit
ECO B28
Move order
1. e4 c5 2. Nf3 a6 3. d4 cxd4 4. Bc4
Ideas
ECO B covers semi-open games after 1. e4 where Black does not reply …e5. White stakes a claim in the center and opens lines for the bishop and queen. This entry tracks a longer branch in the opening tree. Use the diagram and SAN list to recognize the tabiya, then try the line against Maia to explore typical plans in practice.