This is what the line is all about. Carlsen needs to choose carefully.
1. e2e4  1... c7c5  2. g1f3  2... e7e6  3. c2c4  3... b8c6  4. d2d4  4... c5d4  5. f3d4  5... g8f6  6. b1c3  6... f8c5 A line full of chances, especially for blitz. It is an upside-down situation straight from the beginning. Black will be the one ahead in development, and White will have to be careful now. 7. d4c2 The modern continuation. 7... d8b6  8. d1d2 It seems as though the queen is positioned optimally here. 8... f6g4  9. f2f3 