Chess right of a deposed champion to a rematch, and the next champion, Armenian Tigran Petrosian, a player renowned for his defensive and positional skills, held the title for two cycles, 1963–1969. His successor, Boris Spassky from Russia (champion 1969–1972), won games in both positional and sharp tactical style. The next championship, the so-called Match of the Century, saw the first non-Soviet challenger since World War II, American Bobby Fischer, who defeated his Candidates opponents by unheard-of margins and clearly won the world championship match. In 1975, however, Fischer refused to defend his title against Soviet Anatoly Karpov when FIDE did
Interregnum of World Chess Champions Anatoly Karpov after Bobby Fischer), the Interregnum currently remains the only period in the history of modern chess in which there was no World Champion. There was a similar interregnum of the Women's World Chess Championship, between Vera Menchik's death in 1944 and Lyudmila Rudenko winning the championship in 1950. Interregnum of World Chess Champions The Interregnum of World Chess Champions was the period between March 24, 1946 (the date of Alexander Alekhine's death) and May 17, 1948 (when Mikhail Botvinnik won a special championship tournament). When Alekhine suddenly died in 1946, the title of World Chess Champion became vacant