comment: The rook joins the attack.
context: 1. e2e4  1... c7c6  2. d2d4  2... d7d5  3. e4d5  3... c6d5  4. f1d3 Carlsen has played this system many times, with both White and Black. 4... g8f6  5. h2h3 The point of ​​this move is to restrict the development of the c8-bishop. The main ideas of White's setup are using the outpost on e5 and keeping this bishop trapped behind the pawn chain. 5... b8c6  6. c2c3 The disadvantage of this move is that it allows Black to break in the center, freeing up his pieces in exchange for an isolated pawn. 6... e7e5 The most dynamic move. 7. d4e5  7... c6e5  8. d1e2  8... f6e4 A creative and good move. 9. d3b5  9... c8d7  10. g1f3  10... e5g6 A combative move, keeping pieces on the board. 11. c1e3 A new move. 11... f8d6  12. b1d2  12... e8g8  13. b5d7  13... d8d7  14. a1d1  14... f8e8 It is very difficult to predict this in a rapid game, but the rook is best placed on f8, as the analysis will show. 15. d2e4  15... e8e4  16. f3g5 Rapport's brilliant play demonstrates the problem with this move. 16... g6f4  17. e2f3  17... d7b5 White's king is in great danger now. 18. g2g3  18... f7f6  19. g3f4  19... f6g5  20. f4g5 