1. d2d4  1... g8f6  2. c1f4 In the decisive game of the mini-match, Carlsen chooses  his beloved London System. 2... d7d5  3. e2e3  3... c8g4  4. f2f3 There is still  plenty of room for investigation in this line. A bit more than a hundred  games have been played so far. 4... g4d7  5. g2g4 The logical follow-up.  White is not only gaining space; he is also safeguarding his bishop from  the possible trade after the Nf6-h5 maneuver. 5... c7c5  6. c2c3  6... d8b6  7. d1b3  7... e7e6  8. b1d2  8... c5c4  9. b3c2  9... f8d6 As weird as this might sound, this obvious move leads to major difficulties for Black. It is, however, difficult to suggest a good plan  for Black. 10. f4d6  10... b6d6  11. e3e4  11... d6c7 Now it all ends in... a French Defense. 12. e4e5  12... f6g8  13. g1e2 The perfect French Defense arose for White. He has  managed to trade the opponent's good bishop and is already expanding on  the kingside with full speed. 13... b8c6  14. f3f4  14... h7h5 Aronian is trying to somehow block the position. 15. g4h5 White needs files for his pieces. 15... h8h5 