1. Main line 1. d4 Nf6 2. Nf3 b6 3. g3 Bb7 4. Bg2 c5 Choose a line 1. Main line 1. d4 Nf6 2. Nf3 b6 3. g3 Bb7 4. Bg2 c5 2. Berg Variation 1. d4 Nf6 2. Nf3 b6 3. g3 Bb7 4. Bg2 c5 5. c4 cxd4 6. Qxd4 Close 1. Main line 1. d4 Nf6 2. Nf3 b6 3. g3 Bb7 4. Bg2 c5 2. Berg Variation 1. d4 Nf6 2. Nf3 b6 3. g3 Bb7 4. Bg2 c5 5. c4 cxd4 6. Qxd4 Next