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 the match should be of unlimited duration, but the 9–9 clause was once again rejected, by a narrow margin of 35 votes to 32. FIDE set a deadline of April 1, 1975, for Fischer and Karpov to confirm their participation in the match. No reply was received from Fischer by April 3. Thus, by default, Karpov officially became World Champion. In his 1991 autobiography, Karpov professed regret that the match had not taken place, and claimed that the lost opportunity to challenge Fischer held back his own chess development. Karpov met with Fischer several times after 1975, in friendly but