Bird Opening: Siegener Gambit
ECO A02
Move order
1. f4 e5 2. d4 exd4 3. Nf3 c5 4. c3
Ideas
ECO A covers irregular and flank openings—systems that skip the main e4/d4 fight early. White contests the center aggressively from the flank—the Bird family. 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.