context: 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.