Slav Defense, Exchange Variation

LAGOS PORTISCH vs. TIGRAN VARTANOVICH PETROSIAN
Moscow, 1967

1. d4, d5
2. c4, c6
3. cxd5, cxd5
4. Nc3, Nf6
5. Nf3, Nc6
6. Bf4, e6
7. e3, Bd6
8. Bg3, 0-0
9. Bd3, Re8
10. Ne5, Be5
11. dxe5, Nd7
12. f4, Qb6
13. 0-0, Qxe3
14. Kh1, Qb6
15. Qh5, Nf8
16. Rf3, Ng6
17. Bf2, Qd8
18. Nb5, Nce7
19. Nd6, Bd7
20. Bh4, Qb6
21. Rh3 .....

Preparing for attack along the h-file.

21. .... h6
22. Bf6, Qxb2
23. Rf1, Nf5
24. Bxf5 ....

If 24.....exf5 then 25. Bxg7 followed by Qxh6 and mate follows.

If 24......gxf6, then 25. Bxg6 fxg6, 26. Qxf6+ and mate follows.

Black resigns.   Magnifico!!