1. d2d4  1... g7g6 A fact: nowadays, the decisive games often see some irregular  opening choices. The Pirc/Modern defenses are notorious for that. Some  examples that come to my mind are Ivanchuk-Kramnik, FIDE Candidates'  London 2013 and Karpov-Kortschnoi, Baguio City 1978. 2. g1f3  2... f8g7  3. e2e4  Shifting to the Modern/Pirc. 3... d7d6  4. f1c4  4... e7e6 Keeping it as original  as possible. 5. e1g1  5... g8e7  6. a2a4  6... b8d7 Spassky used a similar set-up in his first match against  Petrosian in order to avoid the theoretical lines. Later, however, he  admitted it was a mistake and he went for the main lines in their second  match in 1969. 7. c2c3  7... a7a5  8. f1e1  8... b7b6  9. b1a3  9... h7h6  10. c4d3 Solid and new. 10... c8b7  11. a3c4  11... e8g8  12. d1e2 Centralization and prophylaxis. 12... e6e5 Objectively speaking, a mistake. But such final games have their own  laws and we are not in the position to criticise any of the players'  decisions. 13. d4e5  13... d6e5  14. b2b3 It turns out that Black's position is very  unpleasant. f7-f5 is impossible, there are no outposts for the black  knights. And the rooks are not comfortable as the queen stays on their  road. 14... d8b8  15. c1a3  15... c7c5 Leads to a permanent of the d5 square. But what else could Tan do? 16. a1d1  16... f8d8  17. a3c1 The bishop has done its job, time to change the  operating diagonal. From here it pressurizes the kingside and makes sure  there will be no black bishop out soon. 17... b7c6  18. d3c2 Ju is consistently playing on the d-file and the  queenside. 18... b8c7  19. c4a3  19... g6g5 And the world champion decides to  risk! However: 20. h2h4 Is an excellent counter-strike. White is better prepared for the kingside play. 20... g5g4  21. f3h2  21... h6h5  22. f2f3  22... g4f3  23. e2f3 Black's attack backfired. She loses a  pawn. 23... e7g6 