Defenceman

Defence (defense in the U.S.A.) in hockey is a player position with a primary responsibility to prevent the opposing team from scoring goals. Defence players are often referred to as defencemen, D, or "Blueliners".

In regular play there are two defence players and three forwards on the ice along with the goaltender.

The greatest defenceman in NHL history is often considered to be Bobby Orr who surprisingly managed to win scoring titles while playing defence. Each year the NHL presents the Norris Trophy to the best defenceman in the league.

'Stay-at-home' and 'Offensive defence'
Defence players are generally divided into two rough groups. Stay-at-home defence refers to a defender who takes few risks and does not score much, preferring to focus on defending against the opposing team. An offensive defence player is one who gets aggressively involved in the team's offence and gets used more often as a result. To accomplish this, the offensive defence player often goes deep into the opposing team's zone to get closer to their net. This makes it difficult for the defender to protect his or her own net from being scored on if the other team gains control of the puck. This can lead to more odd man rushes and breakaway opportunities for the opposing team.

Defensive zone play
When in the defensive zone, the defence player is responsible for keeping the opposing forwards' opportunities to a minimum when they are on a rush, forcing them to the corners and blocking both passing and shooting lanes. When the opposing offence is putting pressure on the defence's team, the defence skater usually plays closer to the goal, attempting again to block shooting lanes but also ensure that the goalie is not screened (i.e. prevented from being able to see the puck at all times).

Neutral zone play
In the neutral zone, the defence hangs back towards his or her own blue line, usually playing the puck up to other teammates. According to Jay Leach, who writes for NHL.com's "learn to play hockey" section, the defence must "Move the puck hard and quick to the open man. Join the rush, [but] do not lead it."

Offensive zone play
In the offensive zone, the defence skaters "play the blue line." It is their duty to keep the puck in the offensive zone by stopping it from crossing the blue line that demarcates where the offensive zone begins. Defence players must be quick to pass the puck around, helping their forwards to open up shooting lanes, or taking open shots themselves when they become available. The defence must also be able to skate quickly to cut off any breakaways, moving themselves back into the defensive zone ahead of the onrushing opponent.

Essentially in all three zones of the rink, the defence is the backstop for the puck. It should never go behind the defence, unless the player lets it. The defence keeps the momentum of play squarely directed towards the opposing goal

Backchecking
The backcheck is a play in hockey where a non-defence skater moves back to play defence by keeping an opposing player out of a play through means of checking, stick control, and/or body positioning.

Faceoffs
During faceoffs in the defensive zone, most teams have their defence players pair up with opposing forwards to tie them up while leaving the team's forwards open to move the puck, though this is at the discretion of the individual coach. In the offensive zone, the defence player acts in his or her usual role, keeping control of the puck as the forwards fight for position.

In the first organized hockey, (see Amateur Hockey Association of Canada), defencemen used to line up in an "I" formation behind the rover(defunct) as point and coverpoint. Defence is still referred to as "playing the point".