The winner of the Candidates would qualify to play a World Championship match against Mikhail Botvinnik, the incumbent champion, in 1963.

[1] 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.

Due to Cold War political tension, Wolfgang Uhlmann (East Germany) was refused a visa, causing the players from Bulgaria, Czechoslovakia, Hungary, Poland, and Yugoslavia to withdraw.

The winners of the diminished tournament were Friðrik Ólafsson (Iceland) first with 7½/9 and Andreas Dückstein (Austria) and Rudolf Teschner (West Germany) tied for second with 7.

At its 1961 Congress at Sofia, FIDE decided that Dückstein and Teschner would be allowed to play a match for a place in the Interzonal.

A playoff between the second-place finishers at Berg en Dal ended with Bilek 3½, Bertok and Matanović 3, von Scheltinga 2½.

Tigran Petrosian won the championship with 13½/19, and the remaining qualifiers were Victor Korchnoi with 13 and Efim Geller and Leonid Stein with 12. Notable players who failed to qualify from this zone were former world champion Vasily Smyslov at 11, former world champion challenger David Bronstein at 9, and former Candidates Boris Spassky at 11, Yuri Averbakh at 10½, Mark Taimanov at 10, and Isaac Boleslavsky at 9.

Top finishers in the championship were Bobby Fischer with 9/11, William Lombardy with 7, Raymond Weinstein with 6½, and Arthur Bisguier, Samuel Reshevsky, and James Sherwin with 6.

Fischer and Bisguier won the first two spots, and Pal Benko was nominated to fill the final position.

As the West and Central Asia subzonal tournament at Madras had only two players, it was decided in match play.

Although Stein won, a rule adopted in 1959 allowed no more than three players from a single Federation to qualify from the Interzonal.

Stein could play in the Candidates only if one of the other qualifiers from the USSR (Geller, Petrosian, or Korchnoi) was unable to participate.

The favourites were Tal (the recently dethroned World Champion) and Fischer, based on his powerful Interzonal showing.

[11] Of the others it said: Petrosian had a reputation of drawing many games, and it was unclear if his tendency to split points might prevent him from reaching the championship; Keres at age 46 was the oldest player, and it was thought by some that this might be his last shot at the championship title; Korchnoi and Geller had very imaginative and adventurous styles, which often got them into trouble and led to erratic results; Filip had been ill and had not played many major events between 1958 and 1960, and had the reputation as a solid player who scored many draws; and Benko was not a full-time professional chess player (he worked as an investment broker in New York) which limited his opportunities to play against grandmaster-strength opposition, and he had a tendency to get into time trouble.

[15] After three full cycles (21 rounds), Keres led on 14½, narrowly ahead of Petrosian and Geller on 14, with the others out of contention (Korchnoi 11, Fischer 10, Benko 9, Tal 7, Filip 4½).

The three top finishers (Petrosian, Geller and Keres) drew all twelve of their games against each other, in an average of only 19 moves.

[16] Soon after the tournament, Fischer publicly alleged that the Soviets had colluded to prevent any non-Soviet – specifically him – from winning.

[18] All of the three players involved have since died, but Yuri Averbakh, who was head of the Soviet team, said in a 2002 interview that it was in their interests to draw for reasons not related to Fischer.

[10] He said Keres was the oldest competitor and wanted to conserve energy, and that Petrosian and Geller were good friends with a history of drawing with each other.

[18] FIDE, the world chess federation, responded to the allegations by changing the format of future Candidates' Tournaments.

Petrosian lost the first game of the match, played on March 23, 1963, but recovered and won fairly comfortably, 12½–9½.

[20] The final game, played on May 20, 1963, ended as a draw, giving Petrosian the required 12½ points needed to win the match.