Until the mid-1980s it was generally accepted that ice hockey derived from English field hockey and Indian lacrosse and was spread throughout Canada by British soldiers in the mid-1800s. Research then turned up mention of a hockeylike game, played in the early 1800s in Nova Scotia by the Mi'kmaq (Micmac) Indians, which appeared to have been heavily influenced by the Irish game of hurling; it included the use of a “hurley” (stick) and a square wooden block instead of a ball. It was probably fundamentally this game that spread throughout Canada via Scottish and Irish immigrants and the British army. The players adopted elements of field hockey, such as the “bully” (later the face-off) and “shinning” (hitting one's opponent on the shins with the stick or playing with the stick on one “shin” or side); this evolved into an informal ice game later known as shinny or shinty. The name hockey—as the organized game came to be known—has been attributed to the French word hoquet (shepherd's stick). The term rink, referring to the designated area of play, was originally used in the game of curling in 18th-century Scotland. Early hockey games allowed as many as 30 players a side on the ice, and the goals were two stones, each frozen into one end of the ice. The first use of a puck instead of a ball was recorded at Kingston Harbour, Ontario, Canada, in 1860.

The first recorded public indoor ice hockey game, with rules largely borrowed from field hockey, took place in Montreal's Victoria Skating Rink in 1875 between two teams of McGill University students. Unfortunately, the reputation for violence that the game would later develop was presaged in this early encounter, where, as The Daily British Whig of Kingston, Ontario, reported, “Shins and heads were battered, benches smashed and the lady spectators fled in confusion.” The first organized team, the McGill University Hockey Club, formed in 1877, codified their game's rules and limited the number of players on a side to nine.

By the late 1800s ice hockey competed with lacrosse as Canada's most popular sport. The first national hockey organization, the Amateur Hockey Association (AHA) of Canada (which limited players to seven a side), was formed in Montreal in 1885, and the first league was formed in Kingston during the same year, with four teams: the Kingston Hockey Club, Queen's University, the Kingston Athletics, and the Royal Military College. Queen's University scored a 3–1 victory over the Athletics in the first championship game.

By the opening of the 20th century, sticks were being manufactured, shin pads were worn, the goaltender began to wear a chest protector (borrowed from baseball), and arenas (still with natural ice and no heat for spectators) were being constructed throughout eastern Canada. In 1893 national attention was focused on the game when the Canadian governor-general, Frederick Arthur, Lord Stanley of Preston, donated a cup to be given annually to the top Canadian team. The three-foot-high silver cup became known as the Stanley Cup and was first played for in 1893–94. The first winner was the Montreal Amateur Athletic Association team; since 1917 the cup has gone to the winner of the National Hockey League play-offs.

In 1899 the Canadian Amateur Hockey League was formed. All hockey in Canada at the time was “amateur,” it being “ungentlemanly” to admit to being paid for athletic services. Thus the first acknowledged professional hockey team in the world was formed in the United States, in 1903, in Houghton, Michigan. The team, the Portage Lakers, was owned by a dentist named J.L. Gibson, who imported Canadian players. In 1904 Gibson formed the first acknowledged professional league, the International Pro Hockey League. Canada accepted professional hockey in 1908 when the Ontario Professional Hockey League was formed. By that time Canada had become the centre of world hockey.

The National Hockey Association (NHA), the forerunner of the National Hockey League (NHL), was organized in 1910 and became the strongest hockey association in North America. Rising interest in the game created problems, however, for there were few artificial-ice rinks. In 1911 the Pacific Coast Hockey Association (PCHA) was formed by Joseph Patrick and his sons, who built two enclosed artificial-ice arenas, beginning a boom in the construction of artificial-ice rinks.

The PCHA became involved in a money and player war with the NHA. Although the NHA ultimately emerged as the stronger league, it was the PCHA that introduced many of the changes that improved the game. The only radical rule change adopted by the NHA was to reduce the number of players on a side to six, and that move was made to save money. The western league retained seven-man hockey, but it allowed the goalie to leap or dive to stop the puck. Under the previous rules, a goalie had had to remain stationary when making a save. The western league also changed the offside rule. Under the old rules, a player had been deemed offside if he was ahead of the puck carrier when he received a pass. The PCHA divided the ice into three zones by painting two blue lines across the surface and allowed forward passing in the centre zone between the blue lines. This opened up the game and made it more exciting. Another innovation in the western league was the idea of the assist. Previously, only the goal scorer had been credited with a point. In the PCHA the player or players who set up his goal were credited with an assist. The first numbered uniforms also appeared in their league.

Like some of its predecessors, the NHA had its dissenters. In a move to eject one of the league members, the NHA decided to disband and form a new league. The result was the creation in 1917 of the National Hockey League (NHL), which became the world's foremost professional hockey league. In 1924 the first U.S. team, the Boston Bruins, joined the NHL. In 1925 the New York Americans and Pittsburgh Pirates were admitted, followed in 1926 by the New York Rangers, the Chicago Blackhawks, and the Detroit Cougars (later called the Red Wings). To stock the new teams, the NHL bought out the Patricks' league in 1926 for $250,000. Among the players who shifted to Boston was Eddie Shore, known as a “rushing” defenseman, whose style helped change the game. He was one of the sport's most ferocious and, many experts say, most skilled players, a forerunner of such future NHL players as Gordie Howe (Howe, Gordie), who played mostly for the Detroit Red Wings. The Pittsburgh Pirates and the New York Americans eventually dropped out of the league, and, until the expansion of 1967, the NHL was composed of only six teams: the Rangers, the Bruins, the Blackhawks, the Red Wings, the Toronto Maple Leafs, and the Montreal Canadiens.

In 1967 the NHL undertook one of the greatest expansions in professional sports history when it doubled in size to 12 teams. A new 12-team league, the World Hockey Association (WHA), was formed in 1972, and the ensuing rivalry caused an escalation in players' salaries. In 1979 the NHL, which had grown to 17 teams, merged with the WHA to become a 21-team league; by 1999, 30 teams played in the NHL. In 2004, owners locked out players, insisting that they accept a salary cap that would slow the rapid growth of payroll costs. The players rejected the owners' demands, and the entire 2004–05 season was cancelled. The regular season consists of 82 games and determines the 16 teams that will qualify for the play-offs. The play-off winner is awarded the Stanley Cup.

NHL individual awards are the Vezina Trophy, for the goalie voted best at his position by NHL managers; the William M. Jennings Trophy, for the goalie or goalies with the team permitting the fewest goals; the Calder Memorial Trophy, for the rookie of the year; the Hart Memorial Trophy, for the most valuable player; the James Norris Memorial Trophy, for the outstanding defenseman; the Art Ross Trophy, for the top point scorer; the Lady Byng Memorial Trophy, for the player best combining clean play with a high degree of skill; the Conn Smythe Trophy, for the play-offs' outstanding performer; the Frank J. Selke Trophy, for the best defensive forward; the Jack Adams Award, for the coach of the year; the Bill Masterton Memorial Trophy, for the player who best exemplifies sportsmanship, perseverance, and dedication to hockey; and the Lester Patrick Trophy, for outstanding service to U.S. hockey.

For much of the 20th century, amateur athletes dominated international competition. League competition among amateurs in England began in 1903. The International Ice Hockey Federation (IIHF) was formed in Europe in 1908. Its five original members were Great Britain, Bohemia, Switzerland, France, and Belgium. The first European championship was held at Avants, Switzerland, in 1910, with Great Britain the winner. From that time the federation broadened its membership, taking applicants from the world over. Canada captured the first Olympic Games title in 1920 and, concurrently, the first IIHF world championship. Canada, which also won at the first Olympic Winter Games in 1924, dominated international competition until the emergence of the Soviet team in the early 1960s. The Soviets continued to be the most powerful team in international hockey until the 1990s and the dissolution of the Soviet Union.

In 1995 an agreement between the NHL, the NHL Players' Association, and the IIHF ended amateur domination of international play as professional athletes were allowed to compete at the Olympics and World Cup championships. Although the decision had little effect on the world tournament, the Winter Games competition underwent numerous changes. Given the high visibility of professional players and their skills, selection to the Canadian, U.S., Russian, Finnish, Swedish, and Czech Olympic teams was no longer based on tryouts but rather on the decisions of hockey personnel from each country's national hockey governing body. The six "dream teams" were automatically placed in the final round of eight; the two remaining slots were filled by the winners of a qualifying round. The NHL suspended play for a period of 16 days in 1998 so professional players could make their Olympic debut in Nagano, Japan.

Though considered a male sport, hockey has been played by women for over 100 years. The first all-female game was in Barrie, Ontario, Canada, in 1892, and the first world championship was held in 1990. Recognizing the growing popularity of the sport, the International Olympic Committee added women's ice hockey to its 1998 schedule at Nagano, where the sport made its first Winter Games appearance.

Virtually all equipment—for children, amateurs, or professionals—is the same. Made of vulcanized rubber, the puck is 1 inch (2.5 cm) thick and 3 inches (7.6 cm) in diameter and weighs 5.5 to 6 ounces (156 to 170 grams). Hockey sticks, once made from wood, are now formed from a variety of materials. Rules are enforced limiting the size of the stick and the curvature of its blade. Forwards and defensemen wear the same type of skates, but goaltenders have flatter blades because they need more balance and are stationary for longer periods. The shoes of goaltenders' skates are fitted with rubber protection for the toes. Players wear padding under their uniforms to protect legs, shoulders, and arms. Since 1979–80 all players entering the NHL must wear helmets; helmets and face masks are mandatory in National Collegiate Athletic Association (NCAA) and IIHF play. The goaltender wears a specially designed mask (often molded to the contours of his face) with a plastic guard that protects the throat area.

Over his uniform a goalie wears extra equipment. Pads up to 11 inches (25.4 cm) wide protect him from the tips of his skates to above his knees. They not only afford protection but also aid in blocking shots. On his free hand the goalie wears a glove similar to a first baseman's baseball mitt, with a wide webbing that enables him to catch the puck. The stick hand is encased in a glove with a wide backing that protects his arm. The goalie's stick has a wider shaft and blade than those of the other players. Fully dressed, goaltenders carry up to 40 pounds (18 kg) of equipment.

The modern game on every level—amateur, collegiate, international, and professional—has been influenced largely by the NHL.

Checking—body contact to take an opponent out of play—is permitted anywhere on the ice. In most leagues, including the NHL, players may not make or take a pass that has traveled over a red line and a blue line; if this occurs, the play is ruled offside. A face-off, in which an official drops the puck between opposing players, follows the infraction. In hockey competition that has no red line, an offside infraction involves a pass that has traveled across the two blue lines. Face-offs are held at the point of the infraction. Players who precede the puck into the attacking zone also are ruled offside, and a face-off is held at a face-off spot near the attacking blue line. A face-off also begins each period and is used as well after a goal and after any stoppage of play.

The goalie rarely leaves his goal area. The usual alignments of the other five players are three forwards—the centre, a left wing, and a right wing—and two defensemen—a left defenseman and a right defenseman.

A player may handle the puck as often or as long as he likes, so long as he does not close his glove on the puck or touch the puck with a stick that is higher than shoulder level. A player may not pass the puck with his open hand. The goalie, however, is generally not subject to these restrictions.

The game is divided into three periods of 20 minutes playing time each, with a 15-minute intermission between periods. Hockey games may end in a tie unless the rules stipulate an overtime period to serve as a tiebreaker. In the case of a tie in college hockey, one 10-minute sudden-death overtime period is played in regular season play. NHL teams play a five-minute sudden-death overtime period. During the play-offs, college hockey has 10-minute overtime periods until there is a winner, while the NHL has the same system with 20-minute periods. There is generally no overtime period in international hockey; however, Olympic competition since 1994 has had a 10-minute sudden-death period, followed by a shootout if needed.

In organized ice hockey a victory is worth two points in the standings. A tie is worth one point, and the NHL also awards a point to a team that loses in overtime. A goal counts as a point for the team, but individual points may be awarded to as many as three players for one goal. One point goes to the player who scored the goal, and a point is awarded for an assist to each of the last two of the scorer's teammates who touched the puck, providing that the opposition did not handle the puck in the interim.

Ice hockey is the only major sport in which substitutions are permitted while the game is in play. The game is so fast and so demanding that forwards generally skate only 90 seconds at a time. Defensemen usually stay on the ice for a slightly longer period of time.

Because of the speed and contact, there are many infractions, not all of them having to do with "hitting" penalties. Play is stopped for an offside and for the infraction called icing, which occurs when a team shoots the puck out of its zone past the other team's goal line. Icing is not called against a team when it is shorthanded; if the teams are evenhanded or if the offending team has more players than the opposing team, the puck is returned to the defensive zone of the team that iced it for the face-off. No player, however, may delay the game by intentionally shooting the puck out of the rink or by shifting the goalposts.

Minor penalties are most commonly assessed for excessive use of the body or equipment to impede the opposition. For a minor infraction the offending player must remain in the penalty box at the side of the rink for two minutes while his team plays shorthanded. This man-advantage situation is called a power play. If the opponents score at any time during the penalty period, the penalized player may return to the ice. Penalties incurred by the goalie are served by a teammate. A major penalty for violent play results in the loss of a player for five minutes or for the remainder of the game. If major penalties are incurred simultaneously by both teams, substitutions are made and there is no shorthanded play. A game misconduct penalty for abusing an official results in the loss of a player for 10 minutes; however, a substitution is allowed, and the team does not play shorthanded.

There are three common types of shots in hockey: the slap shot, the wrist shot, and the backhander. The slap shot has been timed at more than 100 miles an hour (160 km an hour). The slap shot differs from the wrist shot in that the player brings his stick back until it is nearly perpendicular with the ice and then brings the stick down in an arc, swatting the puck as he follows through. It is not as accurate as the wrist shot, in which the player puts his stick on the ice near the puck and without a windup snaps his wrist to fire off a shot. The backhander is taken when the puck goes to the other side of the stick from which the player normally shoots. If he is a right-handed shooter, for example, he takes the backhander from his left side. It is taken when there is not enough time to shift the puck to his normal shooting position. The backhander generally is not as hard or as accurate as the wrist shot, but it has the advantage of being taken quickly.

Speed is an essential requirement of the game. In the sport's early days a team could get away with having a few slow defensemen. But contests at all levels became so quick that offensive and defensive roles often are reversed, and defensemen may find themselves at the forefront of the action. Slower players must have other attributes to make a team; they must, for example, be able to check well, to prevent the other players from getting past them. But, since everyone on the team handles the puck at some point during a game, a premium is placed on puck-carrying ability. The man with the puck is in control, and the play can go only so fast as he directs it. Centre Wayne Gretzky (Gretzky, Wayne), while playing for the Edmonton Oilers, was the dominant scorer in the NHL for most of the 1980s due to his outstanding puck handling and his accurate shooting and passing.

If a forward has the puck, the defensemen trail the play. If a defenseman is leading an offensive thrust, called a "rush," one of the forwards backs him up. The opposition, meanwhile, attempts to gain control of the puck or to dislodge it. The most common way is for the defending player to poke his stick at the puck. A defender may also block, check, or hit the player with his body, as long as his action falls within the rules defining allowable contact. Ideally, the defending team's defensemen lay back, straddling their blue line, away from the boards. They then can move to the centre to halt a breakthrough or can drive a man into the boards if he attempts to go along the sides. If the attacking players find that they have difficulty in stickhandling past the opposition, they may try a long shot "on goal." They may also shoot the puck into the other team's zone and chase it, two attacking players going after the puck—one to handle the opponent, who is sure to go after it, and the other to try to wrest the puck away. The third forward, meanwhile, takes up a position about 20 feet in front of the goal, in the centre of the ice, in a spot known as the "slot." In the slot he is in position to shoot if he gets the puck. The defensemen on the attacking team take up positions on the blue line to prevent the defending team from getting a breakaway. Often the puck is passed to the defensemen, who shoot from the blue line, 60 feet out, from their position known as the "point." Long shots rarely go in, so defensemen try to keep long shots low, which gives the attackers a chance at a rebound.

Many fans do not see goals scored in hockey because so many go in on rebounds or deflections. While a shot is taken, no attacking player may be in the goalie's crease, a rectangle eight feet across and four feet out from the goal line; but there is much physical contact in front of the net, and the puck may ricochet off a skate, a stick, or any part of the body. Any kind of shot that puts in a goal is allowable, unless the shooter has raised his stick above his elbow; but the puck may not be deliberately kicked in, and it cannot be thrown in with the hand.

One of the most unusual spectacles in hockey occurs when a team that is trailing by one goal takes its goaltender out of the net in the final seconds of the game. The goalie is replaced by a forward in the hope that the extra man on offense will give the team a chance for a tie. Another rare and exciting play is the penalty shot, which is called when a stick is thrown to deflect a shot or when a player with an open path to the goal is pulled down from behind. The team against which the infraction was committed selects a player to skate unopposed to the opponent's goal and take one shot to beat the goalie; this generally results in a score for the shooting team.

All NHL and international games and many collegiate games are under the control of one referee, two linesmen, and various off-ice officials. Referees are responsible for calling penalties and are the final arbiters of whether a goal has been scored, though the NHL allows officials off ice to review videotape and determine the legality of a goal. Linesmen call offsides and icing infractions; they may also stop play in order to inform a referee that a team has too many players on the ice. In some collegiate games in the U.S. two referees and no linesmen or two referees and one linesman are used, one of the referees being the final arbiter of disagreements. The IIHF sanctions the two-referee system for games under the jurisdiction of national federations. The goal judges are stationed behind each cage in a raised booth behind the boards, and they flip a switch that stops the clock and triggers a red light when they see the puck cross the goal line. The other officials are the penalty timekeeper, the game timekeeper, and the official scorer, who credits players for goals and assists and also keeps track of the goalie's saves, or stops.