World Chess Championship 1966

The 1966 World Chess Championship was played between Tigran Petrosian and Boris Spassky in Moscow from April 9 to June 9, 1966. Petrosian won.

An interzonal tournament was held in Amsterdam in the Netherlands in May and June 1964. Six spots in the Candidates tournament were on the line.

Since FIDE rules only allowed a maximum of three players from the same nation to qualify from the interzonal, Stein and Bronstein were ineligible. Instead Ivkov qualified. The sixth and final place in the Candidates Tournament was decided in a 3-game playoff in which Portisch beat Reshevsky 2½-½.

After the controversy surrounding the previous Candidates tournament, the 1965 tournament was the first to be played as a knock-out series of matches.

Two players were seeded directly into the tournament: Mikhail Botvinnik (loser of the last championship match) and Paul Keres (2nd place in the 1962 Candidates). Botvinnik declined, and his place was taken by Efim Geller, who finished 3rd in the 1962 Candidates.

Spassky won, earning the right to challenge champion Petrosian for the title.

Larsen and Geller played a third place playoff in Copenhagen, Denmark in March 1966. Larsen won 5-4.

The match was played as best of 24 games.

Petrosian retained his title.

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