Formation: Hippopotamus Attack
ECO A00
Move order
1. a3 e5 2. b3 d5 3. c3 Nf6 4. d3 Nc6 5. e3 Bd6 6. f3 O-O 7. g3
Ideas
ECO A covers irregular and flank openings—systems that skip the main e4/d4 fight early. White makes a useful waiting move on the queenside before committing the center. 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.