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
World Chess Championship and Wilhelm Steinitz respectively, played a match. From 1886 to 1946, the champion set the terms, requiring any challenger to raise a sizable stake and defeat the champion in a match in order to become the new world champion. From 1948 to 1993, the championship was administered by FIDE, the World Chess Federation. In 1993, the reigning champion (Garry Kasparov) broke away from FIDE, which led to the creation of the rival PCA championship. The titles were unified at the World Chess Championship 2006. Though the world championship is open to all players, there are separate events and titles for