A bluff?
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. g2g3  3... d7d5  4. f1g2  4... f8b4  5. c1d2  5... b4d6  6. g1f3  6... e8g8  7. e1g1  7... c7c6  8. b1c3  8... d5c4  9. d2g5  9... b8d7  10. c3e4  10... d6e7  11. e4f6  11... e7f6  12. g5f6  12... d8f6  13. d1c1  13... e6e5 Now the position resembles some lines of the Queen's Gambit Declined lines, with the only difference being that  the white bishop is fianchettoed. As a rule the e6-e5 break frees Black's  position and indicates that the worst is over for the second player. 14. c1c4  14... f8e8 A useful move and a novelty. 15. d4e5 Now Black does not experience any problems at all. 15... d7e5  16. c4b3  16... e8e7 Tan prepares the development of the  light-squared bishop and keeps more pieces on the board. 17. f3d4  17... c8g4  18. f2f3 