Editing World Chess Championship (section)

====FIDE system (1963–1975)====
{{further|World Chess Championship 1966|World Chess Championship 1969|World Chess Championship 1972}}

{{multiple image
| align             = right
| total_width       = 350
| image1            = Eerste_ronde_IBM-schaaktoernooi,_Boris_Spasski,_Bestanddeelnr_926-5521.jpg
| caption1          = [[Boris Spassky]] won the World Championship in [[World Chess Championship 1969|1969]], and defended his title against Fischer in [[World Chess Championship 1972|1972]].
| image2            = Bobby Fischer 1972.jpg
| caption2          = [[Bobby Fischer]] ended the 24 years of Soviet domination of the World Championship in 1972.
}}
After the 1962 Candidates, [[Bobby Fischer]] publicly alleged that the Soviets had colluded to prevent any non-Soviet – specifically him – from winning. He claimed that Petrosian, [[Efim Geller]] and [[Paul Keres]] had prearranged to draw all their games, and that [[Viktor Korchnoi]] had been instructed to lose to them. [[Yuri Averbakh]], who was head of the Soviet team, confirmed in 2002 that Petrosian, Geller and Keres arranged to draw all their games in order to save their energy for games against non-Soviet players.<ref name="Kingston2002InterviewAverbakhPart2" /> Korchnoi, who defected from the USSR in 1976, never confirmed that he was forced to throw games. FIDE responded by changing the format of future Candidates Tournaments to eliminate the possibility of collusion. Beginning in the next cycle, 1963–1966, the [[round-robin tournament]] was replaced by a series of elimination matches. Initially the quarter-finals and semi-finals were best of 10 games, and the final was best of 12. Fischer, however, refused to take part in the 1966 cycle, and dropped out of the 1969 cycle after a controversy at 1967 Interzonal in Sousse.<ref name = "Wade-p331">{{cite book
| author1=[[Robert Wade (chess player)|Wade, R.]] | author2=O'Connell, K. | year=1972
| title=The Games of Robert J. Fischer | publisher=[[Anova Books|Batsford]] | pages=331–46
}}</ref> Both these Candidates cycles were won by [[Boris Spassky]], who lost the title match to Petrosian in 1966, but won and became world champion in 1969.<ref name="WeeksFIDEEvents1948to1990">{{cite web|url=http://www.mark-weeks.com/chess/wcc-indy.htm|title=Index of FIDE Events 1948–1990 : World Chess Championship|access-date=16 September 2008|author=Weeks, M.|archive-url=https://web.archive.org/web/20140901124131/http://www.mark-weeks.com/chess/wcc-indy.htm|archive-date=1 September 2014|url-status=live}}</ref><ref name="WeeksAboutFIDEWCC">{{cite web|url=http://chess.about.com/od/worldchampionship/p/aa06c11.htm |access-date=16 September 2008 |title=FIDE World Chess Championship 1948–1990 |author=Weeks, M. |url-status=dead |archive-url=https://web.archive.org/web/20080720005910/http://chess.about.com/od/worldchampionship/p/aa06c11.htm |archive-date=20 July 2008 }}</ref>

In the 1969–1972 cycle Fischer caused two more crises. He refused to play in the 1969 US Championship, which was a Zonal Tournament. This would have eliminated him from the 1969–1972 cycle, but [[Pal Benko]] was persuaded to concede his place in the Interzonal to Fischer.<ref>{{cite web | title=Ed Edmondson Letter | author=Donlan, M. | url=http://www.chesscafe.com/text/edmund.pdf | access-date=16 September 2008 | archive-url=https://web.archive.org/web/20081203222006/http://www.chesscafe.com/text/edmund.pdf | archive-date=3 December 2008 | url-status=live }}</ref> FIDE President [[Max Euwe]] accepted this maneuver and interpreted the rules very flexibly to enable Fischer to play, as he thought it important for the health and reputation of the game that Fischer should have the opportunity to challenge for the title as soon as possible.<ref name="Sosonko2001RememberingEuwePart1">{{cite web | url=http://www.chesscafe.com/text/skittles167.pdf | access-date=16 September 2008 | title=Remembering Max Euwe Part 1 | first=Gennadi | last=Sosonko | author-link=Gennadi Sosonko | year=2001 | publisher=The Chess Cafe | archive-url=https://web.archive.org/web/20110806014241/http://www.chesscafe.com/text/skittles167.pdf | archive-date=6 August 2011 | url-status=live }}</ref> Fischer crushed all opposition and won the right to challenge reigning champion [[Boris Spassky]].<ref name="WeeksFIDEEvents1948to1990" /> After agreeing to play in Yugoslavia, Fischer raised a series of objections and Iceland was the final venue. Even then Fischer raised difficulties, mainly over money. It took a phone call from [[United States Secretary of State]] [[Henry Kissinger]] and a doubling of the prize money by financier [[Jim Slater (accountant)|Jim Slater]] to persuade him to play. After a few more traumatic moments Fischer won the match 12½–8½.<ref>{{cite web
| url=https://www.espn.com/espn/news/story?id=3202460
| access-date=16 September 2008
| title=Fischer, outspoken ex-chess champion, dies of kidney failure
| date=19 January 2008
| publisher=ESPN
| archive-url=https://web.archive.org/web/20080516021931/http://sports.espn.go.com/espn/news/story?id=3202460
| archive-date=16 May 2008
| url-status=live
}}</ref><ref>{{cite web | url=http://www.mark-weeks.com/chess/72fs$$.htm | access-date=16 September 2008 | title=World Chess Championship 1972 Fischer – Spassky Title Match:Highlights | author=Weeks, M. | archive-url=https://web.archive.org/web/20080925034703/http://www.mark-weeks.com/chess/72fs$$.htm | archive-date=25 September 2008 | url-status=live }}</ref>

An unbroken line of FIDE champions had thus been established from 1948 to 1972, with each champion gaining his title by beating the previous incumbent. This came to an end when [[Anatoly Karpov]] won the right to challenge Fischer in 1975. Fischer objected to the "best of 24 games" championship match format that had been used from 1951 onwards, claiming that it would encourage whoever got an early lead to play for draws. Instead he demanded that the match should be won by whoever first won 10 games, except that if the score reached 9–9 he should remain champion. He argued that this was more advantageous to the challenger than the champion's advantage under the existing system, where the champion retained the title if the match was tied at 12–12 including draws. Eventually FIDE deposed Fischer and crowned Karpov as the new champion.<ref>{{cite web | url=http://www.mark-weeks.com/chess/7375$wix.htm | access-date=16 September 2008 | title=World Chess Championship 1975: Fischer forfeits to Karpov | author=Weeks, M. | archive-url=https://web.archive.org/web/20081211095654/http://www.mark-weeks.com/chess/7375$wix.htm | archive-date=11 December 2008 | url-status=live }}</ref> Fischer privately maintained that he was still World Champion. He went into seclusion and did not play chess in public again until 1992, when Spassky agreed to participate in an unofficial rematch for the World Championship. Fischer won the [[Fischer–Spassky (1992 match)|1992 Fischer–Spassky rematch]] decisively with a score of 10–5.