Modern Defense: Semi-Averbakh Variation, Pterodactyl Variation Accepted
ECO A04
Move order
1. Nf3 g6 2. d4 Bg7 3. e4 d6 4. c4 c5 5. dxc5 Qa5+
Ideas
ECO A covers irregular and flank openings—systems that skip the main e4/d4 fight early. White develops a knight and keeps flexible transpositions into d4 or c4 setups. 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.