1. d2d4  1... d7d5  2. c2c4  2... e7e6  3. g1f3  3... g8f6  4. g2g3  4... f8e7  5. f1g2  5... e8g8  6. e1g1  6... a7a5 A rare move that has been played a few times by Carlsen. Its greatest merit is to avoid the more theoretical lines, but it's not a useless move since the pawn on a5 is helpful for Black in some variations, either advancing it to a4, as we will see in this game, or else making the a6-square more comfortable for the black bishop after b7-b6. 7. d1c2 A natural reaction. 7... b8c6 Placing the knight in front of the c-pawn in Queen's Pawn structures is always strategically dangerous. 8. a2a3 [%c_effect a3;square;a3;type;GreatFind;persistent;true] Necessary prophylaxis against 8...Nb4. 8... d5c4  9. c2c4  9... a5a4 This move justifies the development of the knight on c6. It can now go to a5 and b3. 10. b1c3  10... c8d7 Defending the a-pawn and getting ready for ...Na5. 11. c4d3 [%c_effect d3;square;d3;type;GreatFind;persistent;true] When your opponent has a move that she is clearly going to play and that move attacks your piece, remove the piece in advance and only then think about what you're going to do. This is a practical and effective strategy, especially in blitz games. 11... c6a5  12. c1g5 [%c_effect g5;square;g5;type;GreatFind;persistent;true] I'm generally not a big fan of exchanging a bishop for a knight, but here the strategy is typical of the Catalan and fully justified, as White gains central control and solves the problem of the bishop, which didn't have a nice square.