White prepares the expansion in the center.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. a2a3 The Saemisch Variation of the Nimzo-Indian is one of the most risky, optimistic, and ambitious options for White. I've always seen this move as a provocation: White practically ignores Black's previous move and forces him to capture on c3, which could be seen as a waste of time. In the subsequent play, White almost always loses the c-pawn (and this game will be no exception), but seeks compensation by using the center and the bishop pair to fight for the initiative in a sharp position with chances for both sides. 4... b4c3  5. b2c3  5... b7b6 Opening the diagonal for the bishop that will go to a6, combining the attack on the pawn with a knight that is normally maneuvered to a5.