1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... g8f6  4. e1g1  4... f6e4  5. f1e1  5... e4d6  6. f3e5  6... f8e7  7. b5f1  7... c6e5  8. e1e5  8... e8g8  9. d2d4  9... e7f6 One of the most solid lines in the Berlin.  White is trying to squeeze the tiniest of the advantages in a Petroff-like pawn structure. 10. e5e1  10... f8e8  11. c2c3  11... e8e1  12. d1e1  12... d6e8  13. a2a4  13... d7d5  14. a4a5 Since the pieces are far away from any clashes, Yu tries to gain some long-term advantages. Space, for instance. 14... e8d6  15. c1f4  15... c8f5  16. b1d2  16... f6g5  17. e1e3 An obvious and logical novelty. Which  should not challenge the evaluation of the position. 17... g5f4  18. e3f4  18... d8d7  19. d2b3  19... a8e8 Once the rook comes into play on  the open file White has very few resources left to press. 20. b3c5  20... d7c8  21. a5a6 This is the last one, which, however, looks risky. 21... b7b6  22. c5b7 Especially if one needs to self-isolate his knight like this. 22... d6e4 Of course! The knight on b7 does not threaten anyone and  should be left there. 23. a1e1 But Yu has a very concrete idea in mind. 23... f5d7  24. c3c4  24... e4f6 So is carefully avoiding all the tactics so far  and does not mind playing an endgame, especially with a knight on b7 for  White. 25. e1c1  25... d7c6 So decided the time had come to collect the knight.  But this is inaccurate. 26. c4c5  26... e8e4 Now it is not the right time for this.. . 27. f4g3  27... c6b7  28. c5b6 Yu takes the second tactical opportunity and the advanced a-pawn(s) start to pay dividends. 28... b7a6  29. c1c7  29... c8e8  30. f1a6  30... e4e1  31. a6f1 