Pirc Defense, Classical - Schlechter Variation

BORRIS SPASSKY vs. YASSER SEIRAWAN
It (shv.), 1984

1. e4, d6
2. d4, Nf6
3. Nc3, g6
4. Nf3, Bg7
5. h3, 0-0
6. Be3, a6
7. a4, b6
8. Bc4, Bb7
9. e5, Ne4
10. Nxe4, Bxe4
11. Ng5! ....

This sacrificial move intends to open the g-file for White's attack.

11. .... Bxg2
12. Rg1, Bc6
13. Qg4, e6
14. 0-0-0, Nd7
15. h4, dxe5
16. dxe5, Qe7

Black moves the Queen out of harm's way.

17. Rxd7 ....

The Black Knight is much too powerful in his present post.

17. .... Bxd7
18. h5!, f5
19. Qh3 ....

If 19. exf6 Bxf6, 20. hxg6 h6, White's attack fizzles out.

19. .... f4
20. hxg6!! ....

White begins to deliver the final blows.  If 20....hxg6, then 21. Qh7 mate.

If 20.....h6, then the game may continue 21. Bd2, Rae8, 22. Nf7 with a clear advantage for White.

20. .... Bxe5

Black finally takes the e5 pawn, partly to secure the h7 pawn.

21. Nxe6, Bxe6
22. Bxe6+, Kg7

If 22.....Kh8, then 23. Rh1 which adds pressure to the h7 pawn.

23. gxh7, Resigns

If 23. Qxh7+ Kf6, and Black's King manages to escape.

Now, Black's King is forced to retreat:  23.....Kh8, but then comes the crushing blow: 24. Rg8+ Rxg8, 25. hxg8=Q mate.