A new move, played after a long think. This indicates that Carlsen was out of his preparation. His move is an interesting pawn sacrifice.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. d2d4  3... e5d4  4. f3d4  4... g8f6  5. d4c6  5... b7c6  6. e4e5  6... d8e7  7. d1e2  7... f6d5  8. b1d2 This isn't the most popular move, but it was played a few days ago by Erigaisi in a rapid online game, which certainly hasn't escaped Carlsen's team's attention. 8... d5f4  9. e2e3  9... f4d5  10. e3e4  10... f7f6 