A seasoned grandmaster, in the heat of battle, may commit an oversight: a small but fatal mistake that would cost him the game. Bobby Fischer, playing against so many in a simultaneous exhibition tour, clearly made a small flaw -- he forgot his King.
Fischer Simul Exhibition Tour
Houston, 1964
French Defense
1. e4, e6
2. d4, d5
3. Nc3, Nf6
4. Bg5, Be7
5. e5, Nfd7
6. h4 ....
Intending to keep open the h-file as an avenue of attack.
6. .... a6
7. Qg4, f5
8. Qh5+, g6
9. Qh6, Bxg5
10. hxg5, Qe7
Black protects the g7 square.
11. Nh3, Qf8
12. Qh4, c5
13. Nf4, Qf7
14. 0-0-0, cxd4
15. Ncxd5, exd5
16. e6!! ....
16. .... Qg8
17. Nxd5 ....
Black loses his Queen after 17....Qxe6, 18. Nc7+ ....
17. .... Kd8
18. exd7, Qxd5
19. Rxd4, Qxa2
20. Ra4, Qe6
21. Qd4, Qe1+
White resigned.
Black's Bishop would escape death after 22. Qd1 Qxd1, 23. Kxd1 Bxd7 ....
With his last move clearly an oversight, Fischer nevertheless played brilliantly in the entire game.