1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. a2a3 The world champion often chooses this line against the Nimzo-Indian in blitz and rapid. 4... b4c3  5. b2c3  5... c7c5  6. e2e3  6... b8c6  7. f1d3  7... d7d6  8. g1e2  8... e6e5 In return Giri builds the H\FCbner-Portisch  wall. 9. e2g3 A pawn sacrifice which Black sensibly rejects. 9... h7h5  10. h2h4 A novelty. Carlsen understands these positions into the  smallest details and is often getting this same pawn structure as Black  when facing the Rossolimo Sicilian. 10... d8e7  11. d4d5  11... c6b8  12. e3e4 Now Black has a problem with his kingside as he cannot castle  easily. 12... c8g4 In order to lock the diagonal d1-h5.