1. Main line 1. c4 Nf6 2. b4 Choose a line 1. Main line 1. c4 Nf6 2. b4 2. Main line, 3. b4 1. c4 Nf6 2. Nf3 g6 3. b4 Close 1. Main line 1. c4 Nf6 2. b4 2. Main line, 3. b4 1. c4 Nf6 2. Nf3 g6 3. b4 Next