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
Bobby Fischer way to force a draw, yet "sealed a different, wrong move", and lost. "Chess publications around the world wrote of the unparalleled achievement. Only Bent Larsen, always a Fischer detractor, was unimpressed: 'Fischer was playing against children. Fischer, eligible as US Champion, decided against his participation in the 1964 Amsterdam Interzonal, taking himself out of the 1966 World Championship cycle, even after FIDE changed the format of the eight-player Candidates Tournament from a round-robin to a series of knockout matches, which eliminated the possibility of collusion. Instead, Fischer embarked on a tour of the United States and Canada from February