The World Chess Championship has taken various forms over time, including both match and tournament play. While the concept of a world champion of chess had already existed for decades, with several events considered by some to have established the world's foremost player, an event explicitly held to decide a world champion did not take place until 1886. World Championships were initially privately organized matches, with each requiring the consent of the incumbent champion to take place. After 1948, the International Chess Federation (FIDE) began organizing the Championship under its auspices. The championship was fixed to a three-year cycle, with each challenger decided by a Candidates Tournament. In 1993, the short-lived Professional Chess Association (PCA) split from FIDE, and as a result there were two competing World Championship titles between 1993 and 2006.

Key + Date The year the event took place, further disambiguated as needed † Event was a tournament, as opposed to a match. ‡ Event resulted in a draw, with the champion retaining the title. # Scheduled event did not take place. ✻ Event began, but was abandoned without any result. Winner The winner of the event, or the champion otherwise retaining the title. Numerals denote the updated number of event wins or title defences by the champion. Score The performance of the eventual champion. Segments such as tiebreaks are listed sequentially. Head-to-head tournament results are given in a footnote. Runner-up The second-place finisher of the event, or the challenger for a match without a winner References and footnotes corresponding to the event

Predecessor events (before 1886) Chess was first introduced to Europe during the 9th century. In the early modern era, following the solidification of the modern rules of chess, the game continued to carry consistent prestige and public interest. While numerous players have been characterized as the game's strongest over the centuries, the idea of an international chess match or tournament did not occur until the 18th century, and did not materialize until the 19th century. While the following events did not have the title of World Champion at stake, they have been recognized either at the time or in retrospect as indicating the world's leading player.

+ Date Location Winner Score Runner-up Format 1834 London Louis de La Bourdonnais 187456½5½11½6½7½4½45 Alexander McDonnell Casual play 1843 Paris Howard Staunton 138 Pierre Saint-Amant First to 11 wins 1851† London Adolf Anderssen 156 Marmaduke Wyvill Single-elimination tournament with 16 players 1858 Paris Paul Morphy 83 Adolf Anderssen First to 7 wins 1862† London Adolf Anderssen 11½1½ Louis Paulsen Round-robin tournament with 14 players; 1866 London Wilhelm Steinitz 86 Adolf Anderssen Best of 15 1883† London Johannes Zukertort 224 Wilhelm Steinitz Double round-robin tournament with 14 players

Privately organized matches (1886–1946) With both Wilhelm Steinitz and Johannes Zukertort seen as plausible claimants, the two played a match for the first World Championship in 1886. While Steinitz would later claim that he had been the World Champion since the 1860s, no match before 1886 was played for any formal title. From then until after World War II, championship matches were privately organized, and the champion was not formally obliged to face an opponent. An agreement had to be reached between the champion, the challenger, and the patrons sponsoring each match, which included providing the funds for the prize pool. Lasker's 27-year reign as World Champion is the longest in the history of organized chess since 1886, but featured two separate 10-year spans during which he did not defend his title.

+ Date Location Winner Score Runner-up Format 1886 Wilhelm Steinitz 12½7½ Johannes Zukertort First to 10 wins 1889 Havana Wilhelm Steinitz (2) 10½6½ Mikhail Chigorin Best of 20, tiebreak if required 1890–1891 New York City Wilhelm Steinitz (3) 10½8½ Isidor Gunsberg 1892 Havana Wilhelm Steinitz (4) 10102½½ Mikhail Chigorin 1894 Emanuel Lasker 127 Wilhelm Steinitz First to 10 wins 1896–1897 Moscow Emanuel Lasker (2) 12½4½ Wilhelm Steinitz 1907 Emanuel Lasker (3) 11½3½ Frank Marshall First to 8 wins 1908 Emanuel Lasker (4) 10½5½ Siegbert Tarrasch Jan–Feb 1910‡ Emanuel Lasker (5) 55 Carl Schlechter Best of 10 Nov–Dec 1910 Berlin Emanuel Lasker (6) 9½1½ Dawid Janowski First to 8 wins 1921 Havana José Raúl Capablanca 95 Emanuel Lasker Best of 24 1927 Buenos Aires Alexander Alekhine 18½15½ José Raúl Capablanca First to 6 wins 1929 Alexander Alekhine (2) 15½9½ Efim Bogoljubow First to both 6 wins and 15 points 1934 12 cities Alexander Alekhine (3) 15½10½ Efim Bogoljubow 1935 12 cities Max Euwe 15½14½ Alexander Alekhine 1937 9 cities Alexander Alekhine (4) 15½9½ Max Euwe Title vacant from 1946 to 1948, following the death of Alekhine.

FIDE World Championships (1948–1990)

In 1946, Alexander Alekhine died while still holding the title of World Chess Champion. The International Chess Federation (FIDE), which had been founded in 1924, had been attempting to directly participate in organizing the World Championship since at least 1935. By the late 1940s, around half of the plausible contenders for the World Championship were Soviet citizens, and in 1947, the Soviet Chess Federation joined FIDE after decades of declining to do so. FIDE based the 1948 World Chess Championship on the 1938 AVRO tournament that had been organized in part to select a challenger for Alekhine. The tournament ultimately featured five players, three of them Soviet citizens—including the winner, Mikhail Botvinnik. Botvinnik went on to win or retain in four further championship matches. At the same time, FIDE established the rules for the championship going forward. It was organized around a 3-year cycle, during which a series of Zonal and Interzonal tournaments were held, with their highest-scoring performers invited to a Candidates Tournament. The winner of the Candidates tournament in turn played the champion in a match for the title. A defeated champion was entitled to a rematch the following year, after which the 3-year cycle would resume. Botvinnik benefited from this rule twice, in 1958 and 1961.

With the exception of the American Bobby Fischer in 1972, Soviet citizens won every championship from 1948 until the dissolution of the Soviet Union in 1991. With the further exception of Viktor Korchnoi, who had defected from the USSR in 1976, each challenger was also a Soviet citizen. Following his victory, Fischer never played another game organized by FIDE. Disagreements between the two parties—which included Fischer's insistence on a format that required the victor to get a certain number of wins, as opposed to the number of games in a match being fixed—led to his forfeiting the title in 1975. In the absence of a match, FIDE declared Anatoly Karpov, winner of the 1974 Candidates Tournament, to be the World Chess Champion by default.

While the issue had played a role in Fischer's forfeit, FIDE ultimately did change the match format going forward, such that the first to win 6 games would be champion. Under these rules, Karpov twice defended his title against Korchnoi. The next match—which began in September 1984 and featured the 21-year-old Garry Kasparov as Karpov's challenger—ultimately saw 48 games played over the span of five months, with neither player able to get to 6 wins. In an unprecedented step, FIDE president Florencio Campomanes stepped in and declared the match to have ended with no result. A new match, reverted to having a set number of games, was to be played later in 1985. After nearly being knocked out early in 1984, Kasparov defeated Karpov in their rematch. Over the following decade, the two played three more championship matches, with Kasparov narrowly retaining the title in each.

+ Date Location Winner Score Runner-up Format 1948† Mikhail Botvinnik 146 Vasily Smyslov Quintuple round-robin tournament with 5 players 1951‡ Moscow Mikhail Botvinnik (2) 1212 David Bronstein Best of 24 1954‡ Mikhail Botvinnik (3) 1212 Vasily Smyslov 1957 Vasily Smyslov 12½9½ Mikhail Botvinnik 1958 Mikhail Botvinnik (4) 12½10½ Vasily Smyslov 1960 Mikhail Tal 12½8½ Mikhail Botvinnik 1961 Mikhail Botvinnik (5) 138 Mikhail Tal 1963 Tigran Petrosian 12½9½ Mikhail Botvinnik 1966 Tigran Petrosian (2) 12½11½ Boris Spassky 1969 Boris Spassky 12½10½ Tigran Petrosian 1972 Reykjavík Bobby Fischer 12½8½ Boris Spassky 1975# Manila Anatoly Karpov — Bobby Fischer 1978 Baguio Anatoly Karpov (2) 16½15½ Viktor Korchnoi First to 6 wins 1981 Merano Anatoly Karpov (3) 117 Viktor Korchnoi 1984–1985✻ Moscow Anatoly Karpov 2523 Garry Kasparov 1985 Garry Kasparov 1311 Anatoly Karpov Best of 24 1986 Garry Kasparov (2) 12½11½ Anatoly Karpov 1987‡ Seville Garry Kasparov (3) 1212 Anatoly Karpov 1990 Garry Kasparov (4) 12½11½ Anatoly Karpov

Split title (1993–2006)

In 1993, following Nigel Short's victory in the Candidates Tournament, FIDE president Campomanes announced that that year's Championship would take place in Manchester, England. Both Kasparov and Short claimed that FIDE had made this decision without consulting either player, in violation of FIDE's regulations regarding the championship. Kasparov and Short responded by splitting from FIDE and forming the Professional Chess Association (PCA), which organized a World Championship match between the two, played in London later that year. Meanwhile, FIDE stripped Kasparov of his title and organized a championship match between Karpov and Jan Timman, who had finished second and third in the Candidates Tournament. For the 13 years between 1993 and 2006, there were two rival titles. While the PCA itself would fold after only a couple of years, Kasparov would retain what is referred to as "Classical" title, which would be inherited by Vladimir Kramnik upon defeating Kasparov in 2000.

Meanwhile, FIDE once again began experimenting with the championship format. Beginning with the 1998 championship, the system of Zonal, Interzonal, Candidates, and Championship stages was replaced with one single-elimination tournament featuring dozens of players competing for the championship. For the next event in 1999, the incumbent World Champion would not automatically qualify for the finals. Due to this additional change, Karpov—who had won three additional titles during the schism—declined to participate going forward. Each of the four Classical Championships retained a traditional match format.

+ Classical World Chess Championships (1993–2006) Date Location Winner Score Runner-up Format 1993 London Garry Kasparov (5) 12½7½ Nigel Short Best of 24 1995 New York City Garry Kasparov (6) 10½7½ Viswanathan Anand Best of 20 2000 London Vladimir Kramnik 8½6½ Garry Kasparov Best of 16 2004‡ Brissago Vladimir Kramnik (2) 77 Peter Leko Best of 14

+ FIDE World Chess Championships (1993–2006) Date Location Winner Score Runner-up Format 1993 Anatoly Karpov (4) 12½8½ Jan Timman Best of 24 1996 Elista Anatoly Karpov (5) 10½7½ Gata Kamsky Best of 20 1998† Lausanne Anatoly Karpov (6) 3320 Viswanathan Anand Single-elimination tournament with 100 players 1999† Las Vegas Alexander Khalifman 18½11½ Vladimir Akopian 2000† Viswanathan Anand 146 Alexei Shirov 2002† Moscow Ruslan Ponomariov 199 Vasyl Ivanchuk Single-elimination tournament with 128 players 2004† Tripoli Rustam Kasimdzhanov 2010 Michael Adams 2005† Potrero de los Funes Veselin Topalov 104 Viswanathan Anand Double round-robin tournament with 8 players

FIDE World Championships (2006–present)