King's Indian Defense: Orthodox, Modern System

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5 7.O-O Nc6 8.d5 Ne7 9.Nd2 a5 10.a3 Nd7 11.Rb1 f5 12.b4