1. d2d4  1... g8f6  2. c1f4 Firouzja is extremely successful with his London system, introducing a bunch of novelties and concepts at the top-level games he has played. 2... b7b6 \"Some kind of freestyling.\" (Caruana) 3. c2c4  3... c8b7  4. b1c3  4... d7d6 Caruana decided that the King's Indian setup might be a good idea against White's Bf4. 5. g1f3  5... g7g6  6. d4d5 [%c_effect d5;square;d5;type;GreatFind;persistent;true] Shutting out the black bishop. 6... f8g7  7. e2e4  7... e8g8  8. f1d3 \"Quite subtle.\" (Caruana) The bishop is ready to proceed to the a4-e8 diagonal at the first opportunity. 8... e7e5 This turns out to be a novelty. 9. f4d2  9... a7a5  10. a2a3  10... b8a6  11. d3c2 The outcome of the opening is very promising for Firouzja. The black light-squared bishop is very badly positioned, and even if it returns on a working diagonal, it will leave a bunch of holes on the light squares. Moreover, White has not castled yet, and this fact allows him some additional ideas. 11... c7c5 \"I did not want to play this, but I did not know what to do.\" (Caruana) The American GM also explained that he borrowed this idea from the chess engine Leela, which often combines the moves a7-a5 and c7-c5 in the King's Indian defense. 12. d2g5 [%c_effect g5;square;g5;type;GreatFind;persistent;true] The same smart idea from before. Firouzja provokes a kingside weakening. 12... h7h6 Job done. 13. g5e3  13... a6c7  14. h2h3  14... b7c8  15. d1d2 The weakening starts to tell immediately. 15... g8h7  16. g2g4 [%c_effect g4;square;g4;type;GreatFind;persistent;true] All of this is great for White but after 16... a8b8 Firouzja rushed with 17. g4g5 \"I was extremely happy (to see this). At least I get counterplay.\" (Caruana) 17... h6g5  18. e3g5  18... b6b5 [%c_effect b5;square;b5;type;GreatFind;persistent;true] \"I get some counterplay suddenly.\" (Caruana) 19. h3h4  19... c8g4  20. c2d1 This also looks inaccurate. 20... d8d7 Black already has a good choice. 21. h4h5 \"I was very surprised. But it was interesting.\" (Caruana) 21... f6h5  22. f3h4  22... g4d1  23. d2d1  23... f8h8  24. h4f5  24... g6f5 [%c_effect f5;square;f5;type;GreatFind;persistent;true] Black also needs to be careful and must trade the opponent's active pieces. 25. d1h5 