In ice hockey, an official is a person who has some responsibility for enforcing the rules and maintaining the order of the game. There are two categories of officials, on-ice officials, who are the referees and linesmen that enforce the rules during gameplay, and off-ice officials, who have an administrative role rather than an enforcement role. On-ice officials As the name implies, on-ice officials do their job on the hockey rink. They are traditionally clad in a black hockey helmet, black trousers, and a black-and-white vertically striped shirt. They wear standard hockey skates and carry a finger whistle, which they use to stop play. They communicate with players, coaches, and off-ice officials, both verbally and via hand signals. Starting in 1955 with the introduction of the black-and-white jersey, NHL on-ice officials wore numbers on their back for identification. In 1977, NHL officials removed the number and had only their surnames on the back of their jerseys for identification, normally in a single row across the shoulders. (Some officials with long names would have their name in two rows, the most notable example being Andy Van Hellemond.) However, in 1994, NHL officials returned to wearing solely numbers on their shirts, a procedure adopted by other sports leagues. In the early days of hockey when the NHL was formed (1917), the referees would be clad in a vest and tie along with their pants and carry a bell, not a whistle, to stop the game in progress. In those days, penalties were assessed more on common sense rather than following strict rules, and the official would deem what was allowed and not, as well as the length of the penalties. Later, NHL referees wore cream-colored sweaters over a shirt and tie, from the 1930s to the early 1950s. They then briefly wore orange sweaters with half-zip fronts (and without neckties), until the black-and-white-striped jersey was introduced in 1955. Referees A referee is responsible for the general supervision of the game and can be identified by the orange armbands on his or her arms. Ice hockey is a fast-paced sport with high-velocity shots of a puck that is only a few inches in diameter, therefore referees aim to positions themselves so they have specific unobstructed angles of plays in order to make crucial judgment calls as accurately as possible. Under most officiating systems, the referee is the only official with the authority to