Ice hockey is not a complicated sport to follow, but it has three or four rules that stop the play constantly and are almost never explained on the broadcast. Learn what offside, icing and a power play are, and roughly ninety per cent of the whistles in a game suddenly make sense.
Start with the surface. The rink is divided by five lines. A red line runs across the centre; two blue lines sit on either side of it, marking out the attacking and defending zones; and a thin red goal line runs across each end, passing through the net. The area between the blue lines is the neutral zone, and the areas beyond them are the offensive and defensive zones.
Six players a side are on the ice: a goaltender, two defencemen and three forwards. Substitutions happen while play continues, with players climbing over the boards as teammates come off, which is why the composition of a team changes every forty seconds or so without the game stopping.
Offside
The rule is short: the puck must enter the attacking zone before the attacking players do. More precisely, no attacking player may cross the blue line into the offensive zone ahead of the puck. If one does and his team then plays the puck in, the linesman blows the whistle and the restart happens outside the zone.
The purpose is to stop a team from stationing a forward permanently next to the opposition goal waiting for a long pass. Without it, hockey would become a game of hopeful clearances to a camped attacker, which is also why football and several other sports have invented a version of the same rule.
Icing
Icing is called when a player shoots the puck from his own half of the rink all the way across the opposing goal line without anyone touching it. Play stops and the faceoff goes back to the offending team's end, which is the punishment: they have to defend from their own zone.
It exists to prevent a team that is under pressure from simply firing the puck the length of the ice every time it gains possession. There are exceptions. Icing is not called if the team is short-handed, which gives a penalty-killing side a legitimate way to relieve pressure, and it is waved off if an opponent could have played the puck and chose not to.
Penalties and the power play
Most infringements - tripping, hooking, holding, slashing, interference - bring a minor penalty of two minutes. The offending player goes to the penalty box and his team plays with one fewer skater until the time expires or the other side scores. That period is a power play for the opposition and a penalty kill for the team serving it.
More serious offences bring a major penalty of five minutes, which is not cut short by a goal, and the worst bring a misconduct or an ejection. Two players in the box at once leaves a team two skaters short, which is the most dangerous situation in the game and often decides a close match.
Almost every stoppage in hockey is one of three things: the puck went in ahead of the players, the puck went too far, or somebody did something with a stick they should not have.
The delayed penalty
One frequently confusing sequence: when a team commits a penalty but the other side has the puck, the referee raises an arm and waits rather than blowing immediately. Play continues until the offending team touches the puck. The team with possession almost always pulls its goaltender during these seconds, because it cannot be scored against, giving it a brief extra attacker.
It looks alarming the first time you see an empty net in the middle of a game. It is simply a team taking a free advantage that the rule hands them.
Icing used to require an opposing player to actually touch the puck before the whistle, which produced dangerous races to the end boards and some serious injuries. Most leagues now use hybrid icing, where linesmen judge the race to the faceoff dot instead and blow the play dead before the collision.
Faceoffs, periods and overtime
Every stoppage restarts with a faceoff, where two players contest the puck dropped between them. The location depends on what caused the stoppage, and there are nine marked faceoff spots. Winning faceoffs in the defensive zone is a genuinely valuable skill, and specialists are sent on for important ones.
A game is three periods of twenty minutes of actual playing time, which takes considerably longer in real time because the clock stops at every whistle. If the score is level at the end, professional leagues typically play a short overtime with fewer skaters on each side, and if that settles nothing the game is decided by a shootout of penalty shots.
The penalties you will see most
A handful of infringements account for the large majority of whistles. Tripping, hooking and holding all describe using the stick or body to impede an opponent rather than to play the puck. Slashing is striking an opponent with the stick, and high-sticking is making contact above the shoulders, which carries a longer penalty if it draws blood.
Two others confuse newcomers. Interference is checking a player who does not have the puck, which is not allowed even though hockey is a contact sport. And too many men on the ice is a bench penalty, called when a substitution goes wrong and a team briefly has an extra skater - a mistake that looks trivial and regularly costs goals.
Video review and the rest
Goals are reviewed when there is doubt about whether the puck fully crossed the line, whether it was kicked in, or whether the play was offside earlier in the sequence. Coaches may also challenge certain decisions, with a penalty for being wrong, which keeps challenges rare.
Beyond this there are rules about equipment, about how a goaltender may play the puck behind his net, and about conduct, but they rarely affect how a casual viewer follows a game. Offside, icing and the penalty system carry almost all of the explanatory weight. Once those are clear, the sport is remarkably easy to watch.
