From 1962 to 1964 Košler was appointed to the Ostrava opera house, where he worked with foreign ensembles and opera houses, conducted Richard Strauss's opera Salome at the Vienna State Opera, performed the complete cycle of Dvořák's symphonies with the Vienna Symphony.
Košler was appointed to the Ostrava opera house. This was from 1962 to 1964. He worked with foreign ensembles. Opera houses performed the complete cycle of Dvořák's symphonies with the Vienna Symphony. Opera houses were conducted Richard Strauss's opera Salome at the Vienna State Opera.