1. Main line 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. cxd5 cxd5 Choose a line 1. Main line 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. cxd5 cxd5 2. Schallopp Variation 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. cxd5 cxd5 6. Nc3 Close 1. Main line 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. cxd5 cxd5 2. Schallopp Variation 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. cxd5 cxd5 6. Nc3 Next