1. e2e4  1... c7c6  2. g1f3  2... d7d5  3. b1c3 The Two Knights Variation is a good choice for White in the Caro-Kann, ideal for someone who likes to play with the bishops, since in the main line Black quickly exchanges the light-squared bishop for a knight. This reason is probably why it was one of the favorite lines of Bobby Fischer; the American genius had a well-documented preference for positions with a bishop against a knight. 3... c8g4  4. h2h3  4... g4f3  5. d1f3  5... e7e6  6. f1e2 The most popular move nowadays. Interestingly, Keymer is quite used to playing this position as Black, having last played it in an important Olympiad game last year. 6... g8f6  7. e1g1  7... d5d4 It's often said that knights prefer closed positions. If we look at it from that perspective, this move makes a lot of sense, especially since it gains time by threatening the white knight. Fortunately, things in chess are more complicated than that, which is why it's so fascinating. 8. c3b1  8... f8d6  9. c2c3 A rare move. 9... c6c5  10. c3d4  10... c5d4  11. b1a3  11... e8g8  12. a3c4  12... d6c7  13. d2d3 So far, natural play by both sides. Here Black has the option of immediately attacking the c4-knight, although this doesn't change the evaluation of the position (equality). 13... b8c6  14. a2a4 Keymer decides to secure the knight against b7-b5. 14... a7a6 And Praggnanandhaa decides to push b7-b5 anyway. 15. g2g3 This gives the queen a retreating square. 15... b7b5 The natural follow-up. 16. c4a3  16... a8b8  17. a4b5  17... a6b5  18. c1g5 An unpleasant pin, simultaneously vacating the c1-square for the rook. 18... c7d6  19. f1c1  19... c6e5  20. f3g2  20... e5d7 The knight returns before White plays f2-f4. 21. a3c2 Attacking the pawn on d4. White also has another idea, which will be seen in the next move. 21... d8b6  22. b2b4 An excellent prophylactic move, preventing Black's knight from going to c5. White's position has improved, and he now has the typical microadvantage that is promised by the Two Knights Variation of the Caro-Kann. 22... e6e5  23. h3h4 A somewhat mysterious move, although it doesn't change much, given the slow character of the position. 23... b8a8  24. g2f1  24... f8c8  25. a1a8  25... c8a8  26. c1a1  26... b6c6  27. a1a8  27... c6a8  28. f1c1 The position looks harmless, but Black still needs to be careful: if White organizes his pieces, the advantage of the bishop pair can be felt. My impression is that Praggnanandhaa now played a bit too slowly. 28... a8b7  29. e2d1  29... f6e8  30. g5d2 White is preparing Ne1-Nf3-Bb3. 30... d7b8  31. c2e1  31... b8c6 Black counterattacks by pressing the pawn on b4. 32. d1b3  32... c6b4 This changes the character of the game. 33. d2b4  33... d6b4  34. e1f3  34... b7e7 A blunder. 35. c1c6  35... h7h6 Necessary prophylaxis. 36. c6b5  36... b4d6  37. h4h5  37... e8f6  38. f3h4  38... e7d7 Black is holding for now, but the position is very difficult in practice. The light-squared bishop is a monster, and the difference in activity of the knights is also very clear. The f7-pawn will be a constant source of headache. 39. b5a6  39... g8h7  40. a6a2  40... h7g8  41. a2a8  41... d7e8  42. a8a6 The position is a nightmare to defend, since White can try different plans. It's not a surprise that Black quickly makes a mistake.