Lesson
White to move. Main line: 1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4 c5 8. Ne2 O-O 9. O-O Nc6 10. Be3 Qc7 11. Rc1 Rd8 12. f4 e6 13. Kh1 b6 14. f5 Na5 15. Bd3 exf5 16. exf5 Bb7 17. Qd2 Re8 18. Ng3 Qc6 19. Rf2 Rad8 20. Bh6 Bh8 21. Qf4 Rd7 22. Ne4 c4 23. Bc2 Rde7 24. Rcf1 Rxe4 25. fxg6 f6 26. Qg5 Qd7 27. Kg1 Bg7 28. Rxf6 Rg4 29. gxh7+ Kh8 30. Bxg7+ Qxg7 31. Qxg4
Geller builds the attack with f4–f5, Ng3–e4 and both rooks on the f-file. Black’s 24...Rxe4 wins a knight, but it also places the rook where the coming pawn capture opens lines against the king.
After 25.fxg6 f6, 26.Qg5 offers the queen directly. Capturing it would allow the f-file and dark-squared bishop to decide the game; Smyslov declines, but Rxf6 and the h-pawn’s advance leave the king trapped anyway.
The key content angle is tactical immunity. A queen can stand en prise when the recapture opens a mating line. Instead of asking only whether a piece is attacked, calculate what changes after the attacker leaves its defensive square.