Home › Openings › Colle System Colle System: Pterodactyl Variation ECO A40 · 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 Qa5+ Related variationsColle System: Rhamphorhynchus VariationColle System: Siroccopteryx Variation Practice this opening · Play against the computer