1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 - Nimzo-Indian. 4.Qb3 - Spassky! White targets b4 and b7.
White's plans: Play a3, c5, Nf3. Pressure on b4. Black's plans: Play ...Nc6, ...O-O, ...d5. Active development.
Watch the moves to understand the opening sequence. Use the controls to replay or auto-play the variation.