Lesson
White to move. Main line: 1. d4 Nf6 2. c4 g6 3. g3 c6 4. Bg2 d5 5. cxd5 cxd5 6. Nc3 Bg7 7. e3 O-O 8. Nge2 Nc6 9. O-O b6 10. b3 Ba6 11. Ba3 Re8 12. Qd2 e5 13. dxe5 Nxe5 14. Rfd1 Nd3 15. Qc2 Nxf2 16. Kxf2 Ng4+ 17. Kg1 Nxe3 18. Qd2 Nxg2 19. Kxg2 d4 20. Nxd4 Bb7+ 21. Kf1 Qd7
Fischer centralizes with ...e5 and ...Nd3 before 15...Nxf2! removes the pawn shelter and attracts the king. The follow-up ...Ng4+ keeps the initiative while ...Nxe3 attacks White’s queen and pieces.
After the knight takes on g2, Fischer plays ...d4 and ...Bb7+, opening the long diagonal. Byrne resigned after 21...Qd7 because the threats against the king and d4-knight leave White without a satisfactory defense.
This is a useful calculation model: Fischer does not rush to recover sacrificed material. Each move opens another line or attacks with tempo, so White never gets the quiet move required to consolidate the extra piece.