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 1972 he coasted closer to the title, while Spassky lost a chance to fight back. This style of chess offended Fischer. Instead he demanded the format be changed to that used in the very first World Chess Championship, between Wilhelm Steinitz and Johannes Zukertort, where the winner was the first player to score 10 wins, with draws not counting. In case of a 9–9 score, the champion would retain title, and the prize fund split equally. A FIDE Congress was held in 1974 during the Nice Olympiad. The delegates voted in favor of Fischer's 10-win proposal, but rejected the 9–9 clause