Viktor Korchnoi

Viktor Lvovich Korchnoi was a Soviet and later Swiss chess grandmaster and chess writer. He is considered one of the strongest players never to have become World Chess Champion. Born in Leningrad, Korchnoi defected to the Netherlands in 1976, and resided in Switzerland from 1978, becoming a Swiss citizen in 1980. Korchnoi effectively played Anatoly Karpov three times for the World Championship.