1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. g1f3  3... d7d5  4. b1c3  4... f8b4  5. c4d5  5... e6d5  6. c1f4 A relatively  rare move. 6... e8g8  7. e2e3  7... c8f5  8. d1b3  8... b8c6  9. f4g5  9... a7a5  10. g5f6  10... d8f6  11. a2a3 The first  major thought by Black. 11... a5a4  12. b3d5  12... b4c3 And an important  novelty by the former world champion. 13. b2c3  13... c6a5 Caruana won an important central pawn, but is now heavily  lagging in development. Furthermore, his rook on a1 might get in trouble. 14. d5e5  14... f6c6  15. c3c4  15... a5b3  16. e5f5 After almost half an hour on the clock Caruana  decides to part with the troublesome rook. 16... b3a1 