The Memorial Cup, or Mem Cup for short, is the trophy awarded to the national Major Junior men's (under 21) hockey champion of Canada.
The Memorial Cup, originally the OHA Memorial Cup was donated in 1919 by the Ontario Hockey Association (the precursor to the Ontario Hockey League) as a memorial to the Canadian dead of World War I. It was awarded to the junior hockey champions of Canada, much like it is today. With the further division of the junior ranks in 1934 between Junior 'A' and Junior 'B', the Memorial Cup served as the Junior 'A' championship trophy. In 1971, the Junior 'A' rank was further split into the Major Junior rank and a second-tier rank (referred nowadays as Junior 'A'), with the Memorial Cup serving as the Major Junior championship trophy, and the Manitoba Centennial Cup, and later the Royal Bank Cup, serving as the second tier championship trophy.
From 1919 to 1928, the Memorial Cup Final was a two-game total goals affair between a champion from Eastern Canada and a champion from Western Canada, both of which were determined through a series of playdowns under the auspices of the Canadian Amateur Hockey Association. From 1929 to 1971 the Memorial Cup Final was a best-of-three series.
In 1972, the Memorial Cup was contested between three teams: the champions of the three leagues of the Canadian Hockey League: the Western Hockey League, Ontario Hockey League, and the Quebec Major Junior Hockey League, along with a round-robin tournament format and single-game playoff to determine the winner. The 1983 Memorial Cup tournament saw the inclusion of a fourth team, the team hosting the event. As it was to be held in Portland, Oregon, it was also the first American team to qualify (and win) the Memorial Cup. This four team tournament, with the host team being rotated between the three leagues, is the format that continues to be used today.