Canada returned to the IIHF in 1977 after a series of negotiations between IIHF President Dr. Sabetzki and top officials of professional ice hockey in Canada and the United States. As a result, professionals are allowed to compete at the World Championship and the tournament is scheduled later in the year to ensure more players are available from among the NHL teams eliminated from the Stanley Cup playoffs. In return, a competition for the "Canada Cup" was to be played every four years on North American territory with the participation of Canada, the United States, and the four strongest European national teams, including professionals.[citation needed]