E57Black8 book lines continue
Main Line, 8...dxc4 9.Bxc4 cxd4
Nimzo-Indian Defense1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Nf3 d5 6. Bd3 c5 7. O-O Nc6 8. a3 dxc4 9. Bxc4 cxd4
Also known as Nimzo-Indian Defense: 4. e3, Main Line, with 8... dxc4 and 9... cxd4, E57, Nimzo-Indian: 4.e3, main line with 8...dc and 9...cd.