Although the National Hockey League (NHL) follows the general ice hockey rules, they are slightly different from those used by the International Ice Hockey Federation.
The hockey rink is rectangular surface with rounded corners surrounded by boards. In the NHL it is 200 feet (60.96 m) long and 85 feet (25.91 m) wide. The international standard rink measures 60 meters (196.9) long by 30 meters (98.4 ft) wide. The center line, or the “the red line”, divides the rink into two even parts. Two blue lines bound the neutral and the attacking zones and are 1 foot (30 cm) wide. Starting with 2009, a trapezoid is marked behind each net. If the puck is not played into this area, a 2-minute penalty will be assessed.
A goal is scored only if the puck enters the net and is disallowed if the scoring team takes a penalty or if the goaltender interferes with the play. The goal is also not allowed if the puck deflects off a referee or linesman, is directed by an attacker’s high stick or has been thrown into the net with something other than a stick. When the game ends with a tie, it goes into a 5 minute overtime. If a team scores a goal during this time, the game ends and that team wins. If neither of the teams shoot a goal, a 3-frame shootout begins.
An offside occurs when a player enters the offensive zone before the puck, or when an offside player touches the puck. After such violation, a faceoff is conducted in the neutral zone. The only time when a player can precede the puck is when he has control of it no other team member is located in the attack zone.
Penalties are punishments for breaking the hockey rules. Obvious penalties are called by the linesman, although the referee makes the most calls. The linesman can also call major penalties that the referee fails to notice. The player that disobeyed the rules is sent to the penalty box and cannot be replaced. The duration of the penalty depends on the gravity of the infraction, and can reach 5 minutes. If the penalized team scores, the minor penalty terminates. Major penalties must be completed.
According to the national league hockey rules, teams have 18 seconds to substitute players between stoppages of play. This rule does not apply for TV timeouts. Icing happens when a puck is shot across the center line and the opposing team’s goal line and does not enter the goal crease, a blue colored semicircle. If a defending player touches the puck before an attacking player does, the linesman stops the game. The icing is waved off if the goalie makes a move to play the puck. A TV timeout is not allowed after an icing.