The six Interzonal qualifiers were joined by Viktor Korchnoi and Robert Hübner, the Candidates finalists from the previous cycle. The eight players participated in a series of knockout matches. The winner was Garry Kasparov. The Smyslov–Hübner match was originally tied at 5–5. After playing four extra games without breaking the tie, the match was resolved by a spin of the roulette wheel.
Controversies
Politics threatened Kasparov's semi-final match against Viktor Korchnoi, which was scheduled to be played in Pasadena, California. Korchnoi had defected from the Soviet Union in 1976, and was at that time the strongest active non-Soviet player. Various political manoeuvres prevented Kasparov from playing Korchnoi in the United States, and Kasparov forfeited the match. This was resolved when Korchnoi agreed for the match to be replayed in London, along with the Vasily Smyslov vs. Zoltán Ribli match. The Korchnoi–Kasparov match was put together on short notice by Raymond Keene. Kasparov lost the first game, but subsequently won four, prevailing in the match with a total score of 7–4.
1984/85 Championship match
The championship match between Karpov and Kasparov had many ups and downs, and a very controversial finish. Karpov started in very good form, and after nine games Kasparov was down 4–0 in a "first to six wins" match. Fellow players predicted he would be whitewashed 6–0 within 18 games. But Kasparov dug in and battled Karpov to 17 successive draws. He lost game 27, then fought back with another series of draws until game 32, his first-ever win against the World Champion. Another 14 successive draws followed, through game 46. The previous record length for a world title match had been 34 games, the 1927 match between José Capablanca and Alexander Alekhine, which also followed the "first to 6 Wins" format. Games 47 and 48 were both won by the challenger, making the score 5–3 in favor of Karpov and the eventual outcome far less certain. Then the match was ended without result by Florencio Campomanes, the President of the World Chess Federation, and a new match was announced to start a few months later. The termination was controversial, as both players stated that they preferred the match to continue. Announcing his decision at a press conference, Campomanes cited the health of the players, which had been strained by the length of the match. The restarted match was best of 24, with the champion to retain his title if the match was tied 12–12. Because Karpov's two-point lead from the 1984 match was wiped out, Karpov was granted the right of a return match if he lost. The match became the first, and so far only, world championship match to be abandoned without result. Karpov would later say that, if he had won this match 6-0, Kasparov would never have become world champion, because he was too emotional.
