An important move that opens the road for the black knight.
1. d2d4  1... g8f6  2. g1f3  2... d7d5  3. c1f4 The London system is a fearsome weapon in the  hands of the Vietnamise GM. 3... e7e6  4. e2e3  4... f8d6  5. b1d2  5... c7c5 And Caruana  cannot complain of practice in the line as well. In this game he decided  to choose something more complex. 6. c2c3  6... e8g8  7. f4g3  7... b7b6 The same idea to swap off his problematic bishop,  borrowed by the French defense. 8. f1d3  8... c8a6  9. d3a6  9... b8a6  10. d1e2  10... a6b8 The  knight has done it's job and is now moving towards the optimal square.  10...Nb8 scores better than 10...Nc7 and which should not be surpsing as  it is left far away from the central squares. 11. f3e5  11... d8c7  12. e1g1  12... b8c6  13. f2f4 The pawn skeleton has been changed into a reversed Stonewall, where  Le is happy with the aggressive position of his bishop, whereas Caruana  managed to completely get rid of his weak one. 13... c6e7  14. g3h4 [#] 14... f6d7 A natural novelty. This knight has a bright future. 15. a1d1  15... c5d4  16. e3d4 Now tha pawn structure has once more transformed,  this time into a Carlsbad. The plans of the sides are clear- White wants  to mate the opponent on the kingside, whereas Black is looking for a  minority attack on the opposite wing. 16... e7f5 Therefore Caruana  first tames the opponent's initiative on the kingside. 17. h4f2 