How the game is played
The object of the game is to score more goals than the other team. Teams can do so by passing a rubber disk called a puck around to teams and shooting it at a net, which is protected by the other team's goalie. Once a puck goes into the net and fully passes the goal line, it is a goal. At any point during play, a team can have at most six players on the ice - five skaters (defensemen and forwards) and a goalie. Play always begins with a faceoff at a designated faceoff dot, and either team can be on offense or defense at any point in time.
Teams change the players on the ice constantly, through what are called line changes and defensive changes. Before each faceoff, the away team must send out their players first, and then the home team can choose which players to match up with them. However, during play, players can go on and off the ice at any time provided there are only 5 skaters on the ice at any time; the period during which a player is on the ice is called a shift. A shift generally lasts around 45 seconds, although some players like Alexander Ovechkin prefer to have their shifts last over a minute.
The game itself consists of three periods of twenty minutes each. Intermissions between periods last around 17 minutes. During NHL games, there are television timeouts during stoppages in play with 15 minutes left in the period, 10 minutes left, and 5 minutes left. In case of a tie after 60 minutes of regulation play, the game goes into overtime. During the regular season, it is five minutes of four-on-four play, where each team only has four skaters on the ice. The overtime is sudden death, meaning whichever team scores first wins. If there is still a tie after the overtime period, the game goes into a shootout to determine the winner.
The shootout consists of three rounds, with one player from each team shooting per round. Each player goes one-on-one with the goalie, trying to score a goal through individual effort, like in a penalty shot or breakaway. The team that has scored the most out of three rounds wins. If there is still a tie, the teams will go round-by-round until one team scores and the other does not.
There are three zones - offensive zone, defensive zone, and neutral zone. The three zones are separated by the two blue lines. The opposing goalie would be in the offensive zone, and vice versa. The puck must be in the offensive zone before any player of the team on offense, or else that team will be whistled off-sides and a faceoff will occur. If play is in the offensive zone, then if the puck is cleared - i.e. goes out of the zone past the blue line - then all the players who are not defending the zone have to tag up before playing the puck in the zone again.
In the defensive zone, hand passes are allowed (i.e. passing to a teammate using your hand) by the defending team. However, while a puck over glass is allowed in the offensive zone, shooting the puck directly over the glass in the defensive zone is an automatic two minute penalty.
The blue area in front of either goal is called the crease, and is the domain of the goalie. Skaters can enter the crease, but if they interfere with the goalie's ability to stop the puck, a penalty can be called or a goal can be disallowed.
The trapezoid area behind both goals is called, fittingly enough, the trapezoid. It is the only place behind the goal line (the vertical red lines on both ends of the ice) where the goalie can play the puck, or else he will be whistled for a delay of game penalty. This rule is only used in the NHL, and is widely thought to be put into place because of New Jersey goalie Martin Brodeur's ability to play the puck.
One of the most confusing rules in hockey is icing, although once understood it is fairly easy to follow. If a player shoots or passes the puck into the offensive zone before the center red line and it goes behind the goal line without being touched, icing is called. When an icing occurs, the players on the team that committed the icing are not allowed to change and the faceoff goes back into their zone. The other team often sends out their top players on icing calls to try to get the better matchups. However, an icing won't be called if the other team's player could touch the puck before it reaches the goal line, or if the goalie decides to play the puck.
Penalties
There are many different types of penalties in the game of hockey. Most of them fall under the minor category (2 minutes). There are also double minors (4 minutes), majors (5 minutes), and misconducts (10 minutes). All penalties except for misconducts and matching fighting majors make the offending team lose the ability to have a player on the ice for the specified period of time.
A penalty is served by having the player that committed the foul go into the penalty box for the specified period of time. During that time, that player's team can only have four players on the ice, unless another player takes a penalty and in that case there can only be three players on the ice. When a team commits a penalty, they are on the penalty kill; conversely, the other team is now on a power play. The power play lasts as long as the penalty, or until the team on the power play scores, whichever comes first. For a double minor, if the team on the power play scores within the first two minutes of the penalty, they still have two minutes of power play time left. For a major, the team on the power play can score as many goals as they can during the five minute span and the player is not allowed out of the box. Teams can also score shorthanded; that is, they can score while on the penalty kill, although this rarely hapens.
Teams can have matching minors where each penalty cancels each other out and the teams are at even strenght; albeit, they can only play four players each.
Some of the more common minors are: roughing, hooking, holding, slashing, interference, delay of game (puck over glass), delay of game (goalie playing puck outside of trapezoid), delay of game (hand closing over puck), too many men, unsportsmanlike conduct, cross checking, high sticking, instigating, diving, and boarding.
Double minors are only called for roughing (when normal roughing stops just short of fighting) and high sticking that results in injury. An injurous high stick is usually indicated by the presence of blood.
By far the most common major is for fighting, when two players drop their gloves and start punching each other. If both players partake in the fight, then there are matching majors and neither team loses a man. If one player punches another but the other does not fight, the player throwing the punches will be given a fighting major and his team will go on the penalty kill. Other majors include intent to injure, spearing, headbutting, slew footing, and boarding.
Game misconducts are generally give out to players who also got a major, and require them to be off the ice for an additional 10 minutes. Most of the time it means that they are done for the period or the game, but occassionally a player can come back and play. A lot of times game misconducts are paired with match penalties, which automatically eject a player from the game and carry an automatic one game suspension pending league review.
Lineup
During the regular season, the most players one team can have on their roster is 23, which can be allocated any way the team wants. However, for a game, the most players that can play - or "suit up" - is 20 (this does not apply to Olympic hockey; everyone on the team can play in every game). On game days, there are generally twelve forwards, six defensemen, and two goalies who suit up. Sometimes a team goes with eleven forwards and seven defensemen if they feel they need extra support on defense or if they don't have twelve forwards available.
A line consists of three forwards, generally a left wing, a center, and a right wing. Sometimes wingers play on their off wings; i.e. a right winger plays on the left wing, and vice versa. Occassionally a center can also play wing if the team has too many centers or if there is an important faceoff that needs to be won (centers are generally the best players at taking faceoffs).
The top line is generally a collection of the highest scoring forwards on the team. Some teams like to spread around the talent, but the top line is generally the focus of the opposing team's top shutdown defensemen. The second line is less skilled than the top line, but their primary aim is still to score. The third line is expected to score occassionally, but their main focus is to shut down the other team's scoring, tire the other team out, and to provide energy by dishing out hits. The fourth line is often used sparingly, and where teams have their adgitators, enforcers, and defensive energy players. If a team gets offense out their fourth line, it's a bonus; the line is supposed to answer any physical calls (fighting) or try to make the other team take penalties while preventing the other team from scoring.
How the defensemen are arranged varies from team to team. Many teams employ the strategy of pairing an offensive defenseman (one who scores a lot and who handles the puck well) and a shut-down defenseman (one who has little to no offensive talent, but is extremely good at preventing the other team from scoring or getting good scoring chances). Generally, the talent decreases from the top pairing to the bottom, although some teams try to spread defensive talent throughout the pairings.
Most teams have a clear-cut starting goalie and backup goalie (like the New Jersey Devils with Martin Brodeur and Yann Danis or the San Jose Sharks with Evgeni Nabokov and Thomas Greiss), but some employ the 1a, 1b method. Starting goalies play over half the games, generally in the 50-60 games range. Some goalies, like Brodeur and Nabokov, prefer to play over 70 games in a season, and are dubbed "workhorses." Backups, who are usually either less skilled or just less experienced, play the remainder of the games. The 1a, 1b method is where the two goalies split the load fairly evenly, and there's no clear-cut starting goaltender.
Scratches are players who are not playing in the game, due to either not being as good as the other players, having an injury, or having a personal problem. Non-injury scratches are called "healthy scratches," although sometimes healthy scratches have bumps and bruises that they are nursing.
Playoffs
In the NHL, the championship trophy is called the Stanley Cup. Unlike in other sports, the same trophy is used every year. Also, every Cup-winning team gets their entire roster engraved onto the Cup alongside of the past winners. These two facets make the Stanley Cup one of the most sought-after and prestigious trophies in sports.
The playoffs are seperated by the two conferences in the NHL. The top eight teams in each conference make the playoffs, and are arranged by the number of points they accumulate. The winners of the three divisions are automatically seeded in the top three seeds, guaranteeing that they will have home ice in at least the first round. The first round begins with the 1 seed playing 8, 2 seed playing 7, 3 plays 6, and 4 plays 5. Every round is reseeded, so if all four of the top seeds wins their first round series, 1 plays 4 and 2 plays 3.
There are four rounds of best-of-seven series. The higher seed hosts games 1, 2, 5, and 7, while the lower seed hosts games 3, 4, and 6. The first round is the Conference Quarterfinals, the second round is the Conference Semifinals, the third round is the Conference Finals, and the fourth round is the Stanley Cup Finals. The Stanley Cup Finals is the only time where a team from the Western Conference and a team from the Eastern Conference play each other. The playoffs last from early April to mid-June.
There are only a few rule changes from the regular season in the playoffs. The first is an unwritten rule, in that is is harder to draw a penalty in the playoffs. Teams are also a lot more secretive about injuries in playoffs, using terms such as "upper body injury" and "lower body injury" to explain why a certain player is out.
The most prominent rule change in the playoffs is the rule concerning overtime. In the playoffs, an overtime period is just like a regular period, 20 minutes long, except without any television breaks. Overtime lasts until a team scores, causing some games to go into three or four overtime periods (the equivalent of playing another full game) before one team wins the game. Playoff hockey overtime is considered the most intense period of play in sports.