1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 - Nimzo-Indian. 4.Bg5 - Leningrad! White creates immediate tension.
White's plans: Play e3, Qc2, Nf3. Maintain the pin. Black's plans: Play ...h6, ...Bxc3, ...d5. Break the pin.
Watch the moves to understand the opening sequence. Use the controls to replay or auto-play the variation.