Viktor Korchnoi

Viktor Lvovich Korchnoi was a Soviet and Swiss chess grandmaster and chess writer. He is considered one of the strongest players never to have become World Chess Champion. Born in Leningrad, Soviet Union, Korchnoi defected to the Netherlands in 1976, and resided in Switzerland from 1978, becoming a Swiss citizen. Korchnoi played four matches, three of which were official, against GM Anatoly Karpov. In 1974, Korchnoi lost the Candidates Tournament final to Karpov.