Game played on an ice rink by two teams of six players on skates. The object is to drive a puck (a small, hard rubber disk) into the opponents' goal with a hockey stick, thus scoring one point. A game consists of three 20-minute periods. The first true ice-hockey game was played in 1875 between two student teams at Montreal's McGill University. The National Hockey League, consisting of U.S. and Canadian professional teams, was organized in 1917. Hockey was introduced at the Olympic Games in 1920. It is a very aggressive game, and the puck is often taken from a player by means of a hit to the body, called a check. Some contact, such as checking from behind and slashing with the stick, is illegal and draws a penalty. See alsoStanley Cup.