1. e2e4  1... e7e5  2. g1f3  2... g8f6  3. d2d4  3... f6e4  4. d4e5  4... d7d5  5. b1d2 A line that had a burst of popularity some 10 years ago, mainly thanks to the efforts of the  prominent Azerbaijani GM Vugar Gashimov. 5... e4d2  6. c1d2  6... f8e7  7. f1d3  7... c8g4  8. h2h3  8... g4h5  9. e1g1  9... b8d7  10. g2g4  10... h5g6  11. d3f5 White's key idea. Praggnanandhaa fixes his advantage  on the kingside and is patiently waiting for his opponent to castle there.  11... c7c6  12. d2f4  12... g6f5 Liu decided to castle long as soon as possible.  13. g4f5  13... d8b6  14. d1e2  14... e8c8  15. c2c4  15... d5c4  16. e2c4 Too slow. The arising endgame is slightly better for White. 16... b6b4 Black does not miss his chance. 17. c4b4  17... e7b4  18. f4g3 intending to meet f7-f6 with Bg3-h4, but that also  seems a bit sloppy. 18... b4e7  19. f1e1  19... d7c5 Now Black unwinds and the white pawns, mighty in the middlegame, become weaknesses in the endgame. 20. e1e2  20... d8d5  21. a1c1  21... f7f6  22. g3h4  22... e7d8 Liu is outplaying his opponent, the pawn center is about to  collapse and the remnants will disappear. 23. c1c4 Praggnanandhaa understands that the only way to compensate for the static weaknesses is connected with dynamic play. 23... f6e5 