Viktor Korchnoi, a former chess Grandmaster and widely considered to be the greatest player never to have been world champion, died at the age of 85 in Switzerland on Sunday.

Born in the erstwhile Soviet Union, Korchnoi defected to the Netherlands in 1976 at the age of 45 and later moved to Switzerland. He was a candidate for the World Championship on 10 separate occasions, as well as being a four-time chess champion of the Soviet Union. Korchnoi's titanic battles with fellow great Anatoly Karpov, with whom he competed three times, and caught the attention of the entire chess world.

The Grandmaster was also renowned for his longevity – he continued to play tournaments despite his advancing years and was possibly the oldest player to win a national championship when he won the 2009 Swiss championship at the age of 78.