1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... a7a6  4. b5a4  4... g8f6  5. e1g1  5... f8e7  6. b1c3 As far as I know, this is the first time that Carlsen has played this move. It is not as popular as 6.Re1 or 6.d3, but many strong grandmasters have tried it. 6... b7b5  7. a4b3  7... e8g8  8. d2d3  8... c6a5 [%c_effect a5;square;a5;type;Mistake;persistent;true] I wonder whether this is a sacrifice or a blunder. In any case, Black has no compensation for the pawn. 9. f3e5  9... a5b3 