Canada stopped playing in IIHF events in 1970 and Team Canada stopped playing in any games after the team was told they could not use semi-professional players at the World Championship. Canada once again began playing in the IIHF in 1977 after the IIHF President Dr. Sabetzki and top officials of professional ice hockey in Canada and the United States were able to come to an agreement. They agreed that professionals would be allowed to play hockey at the World Championship and the tournament would be scheduled later in the year. This allowed players from the NHL to play, after their teams were no longer playing in the Stanley Cup playoffs. They also agreed to create the "Canada Cup". This championship would be played every four years in North American. Canada, the United States, and the four best European national teams would play in this championship.