The start the final uncovering of the black king.
1. b2b3 Despite the poor start, Carlsen does not mind experimenting. 1... e7e5  2. c1b2  2... b8c6  3. c2c4 Switching to the reversed Sicilian. 3... g8f6  4. g1f3  4... e5e4  5. f3d4  5... f8c5  6. d4f5 This position is super-fresh,  although there is one recent top-GM game. 6... d7d5 Grischuk  played this novelty relatively fast. Apparently, the Russian GM had  studied this line earlier at home. 7. f5g7 Carlsen accepts the pawn without much hesitation. 7... e8f8  8. c4d5  8... c5d4 The point behind Black's play. He wants to trap the opponent's  knight. 9. b1c3 The best chance. 9... c6e7 But this is a mistake! It looks like Grischuk could not  remember some important details. 10. e2e3 Now this is nasty, and Grischuk needs to part with the important  bishop. 10... d4c3  11. d2c3 It is important to open the road for the queen. 11... f8g7  12. c3c4 For the piece Carlsen has two pawns, two bishops and, most  importantly, an eternal attack against the enemy king. 12... e7g6 