# World Chess Championship 1966

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

## 1964 Interzonal Tournament

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.
    1964 Interzonal Tournament 123456789101112131415161718192021222324Total 1 Vasily Smyslov (Soviet Union)–½½½½½½½1111½1½½½½11111117 2 Bent Larsen (Denmark)½–1½010½1½111½½½11½1111117 3 Boris Spassky (Soviet Union)½0–½½½½1110½1½11½111111117 4 Mikhail Tal (Soviet Union)½½½–½½½½½½½½1111½111111117 5 Leonid Stein (Soviet Union)½1½½–01½01½1½1111½½½111116½ 6 David Bronstein (Soviet Union)½0½½1–½½½½1½½1½½111½111116 7 Borislav Ivkov (Yugoslavia)½1½½0½–½½½011½½½½111½11115 8 Samuel Reshevsky (United States)½½0½½½½–½½½½½1½½1½½1111114½ 9 Lajos Portisch (Hungary)000½1½½½–½0½½111½1½1111114½ 10 Svetozar Gligorić (Yugoslavia)0½0½0½½½½–½11½1½1½11011114 11 Klaus Darga (West Germany)001½½01½1½–0½1½1½½11½½1½13½ 12 Levente Lengyel (Hungary)00½½0½0½½01–½½1½1½½1111113 13 Luděk Pachman (Czechoslovakia)½000½½0½½0½½–½1½111111½½12½ 14 Larry Evans (United States)0½½000½00½0½½–1½0111½½1½10 15 Georgi Tringov (Bulgaria)½½000½½½00½000–½1½½1½½119½ 16 Pal Benko (United States)½½000½½½0½0½½½½–½0101½½½9 17 Héctor Rossetto (Argentina)½0½½00½0½0½0010½–½½½01018 18 Alberto Foguelman (Argentina)½000½00½0½½½00½1½–0011018 19 István Bilek (Hungary)0½00½00½½00½00½0½1–½11½½8 20 Oscar Quiñones (Peru)0000½½0000000001½1½–½1½17 21 Yosef Porat (Israel)000000½001½00½½0100½–0½½5½ 22 Francisco José Pérez (Cuba)0000000000½00½½½00001–115 23 Béla Berger (Australia)000000000000½00½11½½½0–04½ 24 Zvonko Vranesic (Canada)0000000000½0½½0½00½0½01–4
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 4-game playoff in which Portisch beat Reshevsky 2½–½.
Bobby Fischer, the winner of the previous Interzonal in 1962, declined his invitation, despite qualifying by winning the 1963–64 US Championship.

## 1965 Candidates matches

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.
| Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Final | Final | Final |
| Riga, Apr 1965 | Riga, Apr 1965 | Riga, Apr 1965 | | | | | | |
| Boris Spassky | Boris Spassky | 6 | | | | | | |
| Boris Spassky | Boris Spassky | 6 | Riga, May–June 1965 | Riga, May–June 1965 | Riga, May–June 1965 | | | |
| Paul Keres | Paul Keres | 4 | Riga, May–June 1965 | Riga, May–June 1965 | Riga, May–June 1965 | | | |
| Paul Keres | Paul Keres | 4 | Boris Spassky | Boris Spassky | 5½ | | | |
| Moscow, Apr 1965 | Moscow, Apr 1965 | Moscow, Apr 1965 | Boris Spassky | Boris Spassky | 5½ | | | |
| Moscow, Apr 1965 | Moscow, Apr 1965 | Moscow, Apr 1965 | Efim Geller | Efim Geller | 2½ | | | |
| Vasily Smyslov | Vasily Smyslov | 2½ | Efim Geller | Efim Geller | 2½ | | | |
| Vasily Smyslov | Vasily Smyslov | 2½ | | | | Tbilisi, Nov 1965 | Tbilisi, Nov 1965 | Tbilisi, Nov 1965 |
| Efim Geller | Efim Geller | 5½ | | | | Tbilisi, Nov 1965 | Tbilisi, Nov 1965 | Tbilisi, Nov 1965 |
| Efim Geller | Efim Geller | 5½ | | | | Boris Spassky | Boris Spassky | 7 |
| Bled, June–July 1965 | Bled, June–July 1965 | Bled, June–July 1965 | | | | Boris Spassky | Boris Spassky | 7 |
| Bled, June–July 1965 | Bled, June–July 1965 | Bled, June–July 1965 | | | | Mikhail Tal | Mikhail Tal | 4 |
| Bent Larsen | Bent Larsen | 5½ | | | | Mikhail Tal | Mikhail Tal | 4 |
| Bent Larsen | Bent Larsen | 5½ | Bled, July–Aug 1965 | Bled, July–Aug 1965 | Bled, July–Aug 1965 | | | |
| Borislav Ivkov | Borislav Ivkov | 2½ | Bled, July–Aug 1965 | Bled, July–Aug 1965 | Bled, July–Aug 1965 | | | |
| Borislav Ivkov | Borislav Ivkov | 2½ | Bent Larsen | Bent Larsen | 4½ | Third place | Third place | Third place |
| Bled, June–July 1965 | Bled, June–July 1965 | Bled, June–July 1965 | Bent Larsen | Bent Larsen | 4½ | Third place | Third place | Third place |
| Bled, June–July 1965 | Bled, June–July 1965 | Bled, June–July 1965 | Mikhail Tal | Mikhail Tal | 5½ | | | |
| Lajos Portisch | Lajos Portisch | 2½ | Mikhail Tal | Mikhail Tal | 5½ | | | |
| Lajos Portisch | Lajos Portisch | 2½ | | | | Bent Larsen | Bent Larsen | 5 |
| Mikhail Tal | Mikhail Tal | 5½ | | | | Bent Larsen | Bent Larsen | 5 |
| Mikhail Tal | Mikhail Tal | 5½ | | | | Efim Geller | Efim Geller | 4 |
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.

## 1966 Championship match

The match was played as best of 24 games, with the champion (Petrosian) retaining the title in the event of a 12–12 tie.
While Petrosian retained the title with a 12–10 lead after Game 22, he and Spassky decided to play the final two games anyway.
This was the first World Chess Championship match since 1934 in which the reigning World Chess Champion defeated his opponent.
World Chess Championship Match 1966 :
| | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | Points |
| Tigran Petrosian (Soviet Union) | ½ | ½ | ½ | ½ | ½ | ½ | 1 | ½ | ½ | 1 | ½ | ½ | 0 | ½ | ½ | ½ | ½ | ½ | 0 | 1 | ½ | 1 | 0 | ½ | 12½ |
| Boris Spassky (Soviet Union) | ½ | ½ | ½ | ½ | ½ | ½ | 0 | ½ | ½ | 0 | ½ | ½ | 1 | ½ | ½ | ½ | ½ | ½ | 1 | 0 | ½ | 0 | 1 | ½ | 11½ |