Torre Attack: Classical Defense, Petrosian Gambit
ECO A46
Move order
1. d4 Nf6 2. Nf3 e6 3. Bg5 c5 4. e3 b6 5. d5
Ideas
ECO A covers irregular and flank openings—systems that skip the main e4/d4 fight early. White builds a pawn center and keeps the position more closed than after 1. e4. 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.