Alekhine, Euwe, Bogoljubov, Flohr, and Sultan Khan, all played in the world elite tournament at Bern in 1932, including the Swiss Hans & Paul Johner, Grob, or Naegeli (who beat reigning World Chess Champion Alekhine in a separate Quadrangular Easter event at Bern the same year).
Much later, the veteran players Geller, Unzicker, Szabo, young Kamsky, Klinger, King, and Korchnoi, dominating a training match for the Olympiad, played in the capital of Switzerland.
Pia Cramling made her final norm to become a *male* GM at Bern during an Open Festival in 1992.
World Elite tournament 1932
The city of Bern featured in July 1932 the probably most important and according to chessmetrics the strongest tournament of the year (followed by the London Sunday Refereee tournament, held in February 1932)
The reigning World Champion triumphed again at Bern, but this time Alekhine lost a game to Bogoljubov in the 10th round. Euwe and Flohr shared second place, one point behind the winner. Sultan Khan finished as clear fourth, Bogoljubov and Bernstein were joint fifth.
At the same time, ten Swiss players in the field competed for the 36th Swiss Championship. The Johner brothers did best with 7 points out of 15 rounds. Hans Johner won the Swiss Championship 1932 based on Sonneborn-Berger score (tie-break).
Max Blau Memorial (I. Invitation) 1987
II. & III. Invitation tournament 1988 & 1989
FIDE Zonal 1990
Training team match with Korchnoi 1992
Volksbank Open series
and Open Predecessors
Three international invitation tournaments had been held from 1987 to 1989 (Campora and Geller won in 1987, Cebalo in 1988, M. Gurevich in 1989), followed by a FIDE Zonal in 1990 (Gad Rechlis from Israel won, he and Eric Lobron from Germany as sole runner-up qualified for the next stage); as well as two longlasting series of Open Festivals in the 1960/70s, and again from 1987 on up into the 21st century.