Nimzo-Indian Defense: Classical, Berlin Variation

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 c5 5.dxc5 Na6 6.a3 Bxc3+ 7.Qxc3 Nxc5 8.b4 Nce4 9.Qd4 d5 10.c5