Carlsen is trying to benefit from the h2-h4 move. He secures the position of his centralized knight.
1. d2d4  1... g8f6  2. c2c4  2... g7g6  3. h2h4 A frequent Anti-Grunfeld line at the World Cup. 3... f8g7  4. b1c3  4... d7d6  5. e2e4  5... b8c6  6. d4d5  6... c6e5  7. f1e2 