As Black
Queen's Indian Defence
The queen's bishop goes to b7 (or a6) to control e4 from afar. Solid and flexible, popular at the very top.
Lines
Against 4.e3
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.e3 Bb7 5.Bd3 Bb4+ 6.Nbd2 O-O 7.O-O d5
Main line: 4...Ba6
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3 Ba6 5.b3 Bb4+ 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5
Petrosian Variation: 4.a3
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5
Classical line: 4...Bb7
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3 Bb7 5.Bg2 Be7 6.O-O O-O 7.Nc3 Ne4
Against 4.Nc3
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.Nc3 Bb4 5.Bg5 Bb7 6.e3 h6 7.Bh4 g5 8.Bg3 Ne4