World Chess Championship 1963

At the World Chess Championship 1963 Tigran Petrosian narrowly qualified to challenge Mikhail Botvinnik for the World Chess Championship, and then won the match to become the ninth World Chess Champion. The cycle is particularly remembered for the controversy surrounding the Candidates' Tournament at Curaçao in 1962, which resulted in FIDE changing the format of the Candidates Tournament to a series of knockout matches.

The world championship cycle was under the jurisdiction of FIDE, the World Chess Federation, which set the structure for the fifth world championship series at the 1959 FIDE Congress in Luxembourg. The cycle began with the zonal tournaments of 1960. The top finishers in the zonals met at the Interzonal, with the top six players from the Interzonal qualifying for the Candidates' Tournament. They were then joined by Mikhail Tal (loser of the last World Championship match in 1961) and Paul Keres (runner-up at the 1959 Candidates) in the eight player Candidates Tournament in 1962. The winner of the Candidates would qualify to play a World Championship match against Mikhail Botvinnik, the incumbent champion, in 1963.

FIDE now had more than fifty member Federations that were divided into nine zones: 1–Western Europe, 2–Central Europe, 3–Eastern Europe, 4–USSR, 5–USA, 6–Canada, 7–Central America, 8–South America, and 9–Asia. Previous championship cycles had used only eight zones. Each zone was allocated from one to four qualifiers based on the relative strengths of its leading players.

The Zonal was held at Madrid, with Jan Hein Donner (Netherlands), Svetozar Gligorić (Yugoslavia), Arturo Pomar (Spain), and Lajos Portisch (Hungary) in a four way tie for first place with 10½/15. A Madrid playoff qualified Gligorić, Pomar, and Portisch.

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