Lesson
White to move. Main line: 1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. Bb5 Bc5 5. O-O O-O 6. Nxe5 Re8 7. Nxc6 dxc6 8. Bc4 b5 9. Be2 Nxe4 10. Nxe4 Rxe4 11. Bf3 Re6 12. c3 Qd3 13. b4 Bb6 14. a4 bxa4 15. Qxa4 Bd7 16. Ra2 Rae8 17. Qa6 Qxf3 18. gxf3 Rg6+ 19. Kh1 Bh3 20. Rd1 Bg2+ 21. Kg1 Bxf3+ 22. Kf1 Bg2+ 23. Kg1 Bh3+ 24. Kh1 Bxf2 25. Qf1 Bxf1 26. Rxf1 Re2 27. Ra1 Rh6 28. d4 Be3
Morphy begins with active piece play rather than an immediate combination. The rook lift to e6, doubled rooks on the e-file and bishop on d7 create the conditions for 17...Qxf3!: after 18.gxf3, the g-file opens with tempo.
The continuation 18...Rg6+ forces the king into a mating net. Morphy repeatedly checks with the rook and dark-squared bishop, then regains decisive material with ...Bxf2 and ...Bxf1. Paulsen’s queen cannot organize a defense despite its nominal value.
Study this game by pausing before move 17 and counting attackers, defenders and forcing replies. The sacrifice works because Black’s pieces cooperate immediately; White’s undeveloped queenside pieces do not. That development gap is the real price of the queen.