Nimzo-Indian Defense: Classical Variation
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2
The Classical Variation against the Nimzo Indian seeks to obtain the two bishops without allowing doubled pawns. White prepares to play a3 and recapture on c3 with the queen. The 4.Qc2 move also fights for the e4-square.
Pros:
Avoids pawn weaknesses
Concentrates on counteracting the Nimzo Indian's ideas
A very critical line
Cons:
White loses time with the queen
Kingside development is delayed