 With NHL players participating in the tournament , IIHF officials began to fear that true amateurs and young players were losing their places . As a result , full world championship status was given to the IIHF World Under @-@ 20 Championship , which had been held annually since 1974 as an unofficial invitational tournament . Colloquially known as the World Junior Hockey Championship , the event was structured after the World Championships , but limited to players under the age of 20 . The World Under @-@ 18 Championship was established in 1999 and typically held in April . It usually does not involve the top North American players because they are involved in University or junior league playoffs at the time . 
