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 carry a bell, not a whistle, to stop the game in progress. 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. are primarily responsible for watching for violations involving the center line and the
blue line. Such infractions include
icing and
offside, after which the linesmen conduct
faceoffs. They are also expected to break up scuffles, fistfights and other altercations that occur during the game. Linesmen to call some penalties (such as
too many players on the ice), and can report major penalties to the referee who may choose to call them.
Assistant referees In some leagues, the linesmen are given the title of the assistant referee. When given this title, they are given more responsibility to stop play and to call penalties that the referee may not see. The
NCAA previously used this designation prior to altering its officiating systems in 2006.
On-ice officiating systems • The
three-official system uses one referee and two linesmen. The NHL previously used this system until changing to the four-official system in the late 1990s. The highest level for this system is the
ECHL, which does official development for the NHL. However, the ECHL is shifting away from this system, with the playoffs and many regular season games using the four-official system. • The
four-official system adds a second referee for a total of two referees and two linesmen. In this system, each referee works either the lead/front or the trail/back position. The lead position is normally in the corner of the end zone, while the trail position is in the neutral zone, diagonally opposite the lead referee. As the game transitions from one end of the ice to the other, the lead becomes the trail and vice versa. The four-official system is used in the NHL,
AHL, and at other high levels, such as major junior, junior 'A', and top European leagues. In 2007-2008, college hockey used the system in some games on a trial basis. The
International Ice Hockey Federation (IIHF) first implemented this system for men's games at the
2008 IIHF World Championship and for women's games at the
2014–15 IIHF European Women's Champions Cup; the four-official system has subsequently been the standard in IIHF competition. The NCAA voted in July 2012 to make the four-official system mandatory for men's games starting in the 2013-14 season. All NCAA games now use the four official system. • In the
two-official system, each official acts as both referee and linesman. Each official has the responsibility to call both penalties and line violations. In this system, neither official wears red or orange armbands or both will wear one armband each. This is used at lower levels of youth hockey and in most adult recreational leagues. • In the
2-1 system, also called the
modified three-man, there are two referees and one linesman. There are a variety of ways to divide the responsibilities between the referees and linesman. For example, on icing plays the linesman will initiate the call and the lead referee will make the determination of whether icing is completed. The 2-1 system is mostly used in American college club hockey (often
ACHA) and
NFHS-certified high school hockey. • The
1-1 system (sometimes called
Texas two-man) uses one referee and one linesman. This is usually seen in adult recreational leagues (sometimes called "beer league" - C, D and I divisions) as a cost-saving measure; the pace of play at this level is typically slow enough for the two officials to cover events between them. This can also be an informal system used
ad hoc when one of the officials does not show up for a game scheduled to use the three-official system, or when an official is hurt during a game. The referee in this system also has the duties of a linesman. • Beginner-level adult leagues sometimes will only use a single on-ice official who is responsible for calling line violations and penalties. The official will not usually wear orange or red armbands in this system. == Off-ice officials ==