1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... d7d5 The Queen's Gambit is an essential guest at world championships, with memorable games in the legendary clashes between Capablanca vs. Alekhine, Spassky vs. Fischer, and Karpov vs. Kasparov, among others. 4. c4d5 The exchange variation was Kasparov's favorite. 4... e6d5  5. c1g5  5... c7c6  6. e2e3  6... h7h6 In the 90s, moving the h-pawn in the Exchange Orthodox positions like this was considered an opening mistake. This is one of the clearest changes in theory in recent years. The computer showed that it's OK to play like this and also started to indicate more active plans for Black, like advancing the queenside pawns with b7-b5 and a7-a5, which was also considered anti-positional. 7. g5h4  7... f8e7  8. f1d3  8... e8g8 Ding has some experience in this position, so it didn't come as a surprise to Nepomniachtchi. Two of the Chinese GM's opponents decided not to put the queen on c2 so quickly, but he had no trouble equalizing in those games. 9. d1c2  9... f8e8  10. g1e2  10... b8d7  11. e1g1  11... a7a5 Ding repeats what he had played in a rapid game against Giri last year. Black has options that are more popular. 12. a2a3 This is not an easy move. I think the idea is to already prevent the …b5-b4 advance, although it's a bit curious that this is done before the pawn reaches b5. 12... f6h5 A classic Queen's Gambit move, exchanging bishops and relieving the position. 13. h4e7  13... d8e7  14. a1e1 White goes to the center. The plan is Nc1, f3, and play e4 at an opportune moment, but Black will avoid this in the game. 14... d7f8  15. e2c1  15... h5f6  16. f2f3  16... f8e6 Ding had played all this before and only here a novelty is played. Nepomniachtchi didn't get any advantage and will need a better idea if he wants to repeat this opening. 17. c1e2  17... c6c5 Ding follows the same plan as his game against Giri. 18. d3b5  18... e8d8  19. d4c5  19... e7c5 