1. Main line 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 Qa5+ Choose a line 1. Main line 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 Qa5+ 2. Colle System: Siroccopteryx Variation 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 cxd4 5. Nxd4 Qa5+ Close 1. Main line 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 Qa5+ 2. Colle System: Siroccopteryx Variation 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 cxd4 5. Nxd4 Qa5+ Next