Van Geet Opening: Pfeiffer Gambit, Sleipnir Countergambit
ECO A00
Move order
1. Nc3 d5 2. f4 d4 3. Ne4 e5 4. Nf3
Ideas
ECO A covers irregular and flank openings—systems that skip the main e4/d4 fight early. White develops the queen's knight while leaving central pawn breaks open. 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.