context: 1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... g8e7 This is the Cozio Variation of the Ruy Lopez, and it has appeared in other \"Games of the Day.\" Nakamura has used it a few times with Black but not often. He played a game with White against Caruana in 2024 that may have sparked his idea to play it with the other color. 4. b1c3 White has three other major moves. 4... e7g6  5. d2d4  5... e5d4  6. f3d4  6... c6d4  7. d1d4  7... c7c6  8. b5e2  8... d8b6  9. d4d3 All of White's moves are very natural, and this is a critical line for Black's system. 9... f8e7  10. a2a4  10... a7a5  11. e1g1  11... e8g8  12. c1e3 Now White can play this move without having to sacrifice a pawn, since with the inclusion of a4-a5, the queen is left without a square. 12... e7c5  13. e3c5  13... b6c5  14. a1d1  14... g6e5 A bad move, since the knight will soon be attacked by f4 and White remains with a firm grip on the dark squares. 15. d3d6  15... c5d6  16. d1d6 The endgame is nearly winning for White with a development advantage and better pawn structure. Black has trouble getting the bishop into play, and the backward d-pawn is a long-term weakness. 16... f7f6  17. f2f4  17... e5f7  18. e2c4  18... g8h8  19. d6d4 Carlsen decides to keep the bishop to advance the pawn to e5 to create problems quickly for Black. 19... b7b6  20. e4e5  20... f7h6  21. c3e4 