1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Be2 O-O - See KID. 6.Bg5 - Averbakh! White pins or controls key squares.
White's plans: Play Qd2, f3 or Nf3. Control the center. Black's plans: Play ...c5, ...Nbd7, ...a6. Break in the center.
Watch the moves to understand the opening sequence. Use the controls to replay or auto-play the variation.