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. 13. f2f3  13... g4c8  14. c1g5 Nevertheless. The pin is extremely unpleasant for  Giri. 14... e7c7 He breaks it at once, but this leaves his kingside in  ruins. 15. g5f6  15... g7f6  16. e1g1  16... b8d7  17. f3f4 Black's kingside crumbles. 17... e5f4  18. g3h5  18... d7e5  19. h5f6 Forcing matters. 19... e8d8  20. f1f4  20... e5g6  21. d1f3 Excellent stuff! The world champion  is ready to spend an exchange for the anti-blocker. By doing so he also  secures the excellent position of his knight on f6 (which is definitely  not weaker than any of the black rooks) and, yes, the h-passer remains  alive. 21... c7e7 