Originally posted by Paul Leggett
"He studied and played all manner of openings just like ALL GM's do."
This is not a very accurate description of Fischer's play. The "studied" part is reasonable, but that's about it.
He did start to vary his routine a bit on the way to the Championship to keep the Soviets guessing, but his repertoire was still very narrow compared to many top players.
In his last active years he did try closed games as White - inspired by the famous caricature of Boris and Leonid - "Boris, what if he doesn't play 1/ e4" - and maybe feared of how narrow his repertoire was - but you can notice in his games as white that he uses first opportunity to convert position into an open kind.
He played King Ind Attack often, and he just reverted what he developed from Boleslavskiy's games (he was the only man in the West who had read that book!).
But I say this only and simply because it's true.
It's not a criticism.
It is even more amazing how he managed to emerge as the best with such narrow repertoire when he knew that his opponents might had prepared for him.
He saved a lot of his variants during Palma de Mallorca interzonal by playing KID Attack etc., or by playing reversed Sicilian (into which 1. b3 turned in his interpretation) but what he did against Spassky wasn't real change in repertoire:
he just did amazingly what Spassky missed - to prepare for enemy's repertoire
- Fischer's play against Makagonov-Bondarevsky Queen Gambit
or his application of KID tricks in Nimzoindian - it was one time tricks, not real conversion into closed games [edit - or quitting KID and Ben Oni].
That narrowness only adds a legend to Fischer's rise.