1. d2d4  1... d7d5  2. c2c4  2... e7e6  3. g1f3  3... g8f6  4. g2g3  4... f8e7  5. f1g2  5... e8g8  6. e1g1  6... d5c4  7. d1a4 7.Qc2 is the most popular move. The idea of the move played is to avoid 7...b5. 7... a7a6 The downside is that now White cannot play 8.a4, an option that is possible when the queen is on c2. 8. a4c4  8... b7b5  9. c4c2  9... c8b7  10. c1d2  10... b7e4  11. c2c1 One of the most important positions in the Catalan Opening, with thousands of games. 11... b8c6  12. d2e3 Defending the d-pawn and preparing to develop the knight on d2. 12... a8c8 The idea is to get the rook off the unpleasant diagonal and support the future c7-c5 push. 13. f1d1  13... f6d5  14. b1d2 [%c_effect d2;square;d2;type;GreatFind;persistent;true] Accepting a change in the pawn structure. 14... d5e3  15. f2e3  15... e4f3  16. e2f3 [%c_effect f3;square;f3;type;GreatFind;persistent;true] The most accurate way of recapturing. 16... c6b4 This new move was played after some thought; maybe Tan's preparation was over at this point. 17. a2a3 A good move, dispatching the knight. It's also possible to control the c5-square immediately. 17... b4d5  18. d2b3  18... f7f5 [%c_effect f5;square;f5;type;Inaccuracy;persistent;true] Tan wants to make it difficult for the e-pawn to advance, but this move creates weaknesses. 19. d1d3  19... g8h8 [%c_effect h8;square;h8;type;Inaccuracy;persistent;true] 20. c1c6 [%c_effect c6;square;c6;type;GreatFind;persistent;true] The position becomes dangerous for Black. 20... d5b6 [%c_effect b6;square;b6;type;GreatFind;persistent;true] An excellent move, preparing counterplay before the position becomes passive. 21. b3a5 [%c_effect a5;square;a5;type;Inaccuracy;persistent;true] 21... e6e5 [%c_effect e5;square;e5;type;GreatFind;persistent;true] Now the game becomes sharp. 22. a1c1 [%c_effect c1;square;c1;type;Inaccuracy;persistent;true] 22... e7f6  23. g2h3 