Fortress • Karpov - Mestel, London 1982

The position in the diagram is from game 28 in Karpov's 'Chess at the Top'. Karpov played 28.g5!, and commented, 'An important move! Although the Pawn is placed on a black square (with the opponent having a black-squared Bishop), by cutting off the Black King it assists the creation of mating threats. Had Black succeeded in playing ...g5 and securing control of the 7th rank, his position would have become impregnable, or, as usually called, a "fortress".'

The game continued 28...d5 29.Rb8+ Kg7 30.Re8 Bc3+ 31.Kd1 Bd4 32.Rf3 Rf7 33.Rxf7+ Kxf7 and Mestel resigned on his 40th move.

London 1982
Mestel, Jonathan

Karpov, Anatoly
(After 27...Rc3-c7)
[FEN "6k1/p1r5/3pp1p1/4b3/6P1/8/P1PK1R2/1R6 w - - 0 28"]

Karpov's positional understanding is light years ahead of mine. How on earth did he see that with the White Pawn on g5 the position is won, but with the Black Pawn on g5 it is drawn? Amazing!

To play through the complete game see...

Anatoli Karpov vs Andrew Jonathan Mestel, 5, London P&D 1982
http://www.chessgames.com/perl/chessgame?gid=1068306

...on Chessgames.com.