In order to free an outpost for her second knight.
1. c2c4  1... e7e6  2. b1c3  2... d7d5  3. d2d4  3... g8f6  4. c4d5  4... e6d5  5. c1g5  5... c7c6  6. e2e3  6... h7h6  7. g5h4  7... f8e7  8. f1d3  8... f6e4  9. h4g3  9... e4g3  10. h2g3  10... b8d7  11. g1f3 Obvious and natural. 11... d7f6  12. d1c2  12... c8e6  13. e1c1 In a Carlsbad Pawn structure both  players castle long in order to avoid the kingside attack. 13... d8c7  14. c1b1  14... e8c8  15. c3a4 Goryachkina's position seems more pleasant as she  has clear spots to occupy with her knights. At the same time Ju's bishop  pair is idle, but should not be underestimated. 15... c8b8  16. a4c5  Without much hesitation, the world champion decided to get rid of both  white knights. After all, this is presumably one of the advantages of the  bishop pair. 16... e7c5 