As a champion, he used his eccentricities to unsettle opponents, but Fischer's reputation as a genius of chess was soon eclipsed, in the eyes of many, by his idiosyncrasies.
Fisher died of kidney failure Thursday in a Reykjavik hospital after a long illness, his spokesman, Gardar Sverrisson, said today
Kirsan Ilyumzhinov, president of the World Chess Federation, called Fischer "a phenomenon and an epoch in chess history, and an intellectual giant I would rank next to Newton and Einstein."
He spent nine months in custody before the dispute was resolved when Iceland granted him citizenship and he moved there with his longtime companion, the Japanese chess player Miyoko Watai. She survives him.
In his final years, Fischer railed against the chess establishment, alleging that the outcomes of many top-level chess matches were decided in advance.
Instead, he championed his concept of random chess, in which pieces are shuffled at the beginning of each match in a bid to reinvigorate the game.
"I don't play the old chess," he told reporters when he arrived in Iceland in 2005. "But obviously if I did, I would be the best."
Born March 9, 1943, Robert James Fischer was a child prodigy, playing competitively from age 8