Benoni Defense: Modern, Classical, Averbakh-Grivas Attack

1.d4 Nf6 2.c4 c5 3.d5 e6 4.Nc3 exd5 5.cxd5 d6 6.e4 g6 7.Nf3 Bg7 8.Bg5 h6 9.Bh4 a6 10.Nd2 b5 11.Be2