Here are some (but definitely not all) of the major IIHF rule changes since 1911:
On March 14, 1911, the Ligue Internationale de Hockey sur Glace (LIGH) was renamed the International Ice Hockey Federation (IIHF) and officially adopted the Canadian rules at that time for amateur play. Before this, bandy rules were used in European hockey. Games consisted of two 30-minute periods. Teams featured seven-man lineups (a goaltender, two defencemen, a rover and three forwards)--and countries were permitted to carry only two substitutes.
In 1913, it marked the first time teams wore numbers on their backs. World War I interrupted play and rules changes for 6 years.
At the 1920 hockey tournament in Antwerp, Belgium, teams from Canada and USA participated for the first time and helped to adjust the rules of both the IIHF and the Canadian game. There would be six players per side (the rover having been dropped at the IIHF Congress in March of 1912) and players could only be changed when the action was stopped. The 1920 tournament was played on a rink that was different in size from that prescribed by the IIHF rules.
In 1921, teams would now be permitted to carry 11 players on their rosters. Games would still consist of two 30-minute periods.
At the 1924 Winter Olympics, this competition was played according to new rules that divided the game into three 20-minute periods.
In 1925, the IIHF Congress established a minimum rink size of 18 metres (58 feet) wide by 50 metres (163.5 feet) long, with regulation size being 26 metres (85 feet) by 56 metres (184 feet). Body checking was introduced in the defensive zone. These new rules were applied at the 1926 European Championships.
The 1929 European Championships marked the last time that games in this competition were played in two periods of 30 minutes.
At the 1930 World & European Championships, the IIHF presented medals to winners instead of diplomas that it had handed out in the past. Also, other firsts included allowing forward passing in the defensive zone and a new rule calling for three 15-minute periods.
In 1933 at the seventh World Championship, forward passing in any zone on the ice was featured for the first time.
At the 1936 Winter Olympics in Germany, a goalie (Japan's Teiji Honma) wore a face mask for the first time in World Championship play.
In 1937, teams were now permitted to use 14 players on their rosters and lineups usually included two goaltenders, three defencemen and three forward lines.
The first post-world war II congress of the IIHF was held in Brussels in April of 1946
and introduced some very important rule changes to international hockey. Three periods of 20 minutes, which had been introduced in Europe in 1945, were approved at the meetings in 1946 (35 years later than Canada). Also approved was the modern size of 183 centremetres (6 feet) by 122 centremetres (4 feet) for the goalie net, plus a goal line and centre-ice red line. One- and three-minute penalties were omitted from the rules and a penalty shot was introduced.
At the 1967 World Championships, the IIHF increased roster sizes to 18 players.
In 1969, roster entry lists increased to 19. A drug-testing policy was introduced by the IIHF at its congress in July of 1969 and first implemented at the Winter Olympics in Sapporo in 1972.
The appointment of Dr. Gunther Sabetzki to the position of IIHF president in July of 1975 led to a declaration that professional players would be allowed to compete beginning with the 1976 World Championships and also to make the rules of amateur hockey more consistent with those of the pro game. This included the termination of a two-minute penalty as soon as the team on the power-play scored, the elimination of icing for teams playing short-handed, and the introduction of delayed penalties.
During the May 1978 IIHF congress, the IIHF seeking to further perfect the game did much to make the amateur and professional rules more consistent. Other decisions adopted that went into effect at the 1979 World Championships included making it necessary for the defending team to touch the puck before icing was called, abandoning the change of ends in the middle of the third period when games were played indoors, and increasing rosters to 22. Olympic tournament roster sizes were still at 20 players.
For the 1983 World Championships, the IIHF congress ruled that teams must provide a preliminary entry list of not less than 19 players, with the remaining three roster spots eligible to be filled during the course of the championships. These new rules were introduced in order to better balance the competition for medals.
Several months before the start of the 1988 Olympic hockey tournament in Calgary, the decision was made to allow teams to include professional players on their rosters.