Interzonal
Interzonal chess tournaments were tournaments organized by
FIDE, the
World Chess Federation. They were a stage in the
World Chess Championship cycle. Basically, the plan was that the cycle would last three years. In the first year, every FIDE member nation would hold a national championship. The top players would qualify to the Zonal tournament. The world was divided into zones. Large countries such as the
USSR and the
United States had their own zone. Smaller countries would be grouped into a zone with many countries. For example, all of South and
Central America combined was originally just one zone. There were originally no Asian or African zones, because there were no countries in those continents that were members of FIDE.
The top players in each Zonal tournament would come together and play in the
Interzonal tournament. Typically, the Interzonal tournament would have about 24 players. Then, the top six would qualify to the
Candidates Tournament, that would take place the following year. Those six would join with the top two from the previous candates tournament from three years earlier. These eight players would play mini-matches against each other. The winner of those matches would play a 24 game match with the World Champion the following year.
To illustrate, in 1957 the US Championship was held. The top three,
Bobby Fischer,
Samuel Reshevsky, and
James Sherwin qualified to the Interzonal Tournament that was held in
Portorož in 1958. The top six at Portorož, which included
Mikhail Tal,
Pal Benko,
Friðrik Ã"lafsson and
Bobby Fischer qualified to the
Candidates tournament. They were joined by
Vasily Smyslov and
Paul Keres who had been the top two at the 1956
Candidates tournament. Those eight played four games each against each other in 1959. The winner was
Mikhail Tal, who then played
Mikhail Botvinnik a match for the world chess championship in 1960. Also in 1960, a new three-year cycle, with
Bobby Fischer,
William Lombardy and
Raymond Weinstein qualifying from the
US Chess Championship, started.
Thus, Interzonal tournaments were held every three years from 1948 until 1993. However, by 1972, the system was becoming unwieldy. There were far too many top level players and the cost of staging these events had become too great. Also, new countries were joining, especially in
Asia.
China,
India,
Indonesia and the
Philippines started producing top level grandmasters where there had been none before. Even
Africa was demanding two zones. It was not practical to put all the top players in a round robin tournament. So in 1973 the system was changed to two Interzonals (with usually the first three in each qualifying for the Candidates), then in 1982 it changed again to three Interzonal tournaments. Further increases led to the Interzonal being staged as a single
Swiss system tournament in 1990 and 1993.
The most famous Interzonal tournaments were
Stockholm 1948 won by
David Bronstein,
Saltsjobaden 1952 won by
Alexander Kotov, Portorož 1958 won by
Mikhail Tal,
Stockholm 1962 won by
Bobby Fischer and
Sousse 1967 won by
Bent Larsen. (Note: the 1962 Interzonal was supposed to have been held in 1961 under the three-year schedule, but had to be postponed one year because of lack of funds.)
The last
FIDE Interzonal was
Biel 1993, won by
Boris Gelfand. The short-lived
Professional Chess Association also held one Interzonal, in 1993.
*
Mark Weeks' World Chess Championship Index
