In hockey, traps happen when the neutral zone on the ice becomes "clogged," meaning the defenders won't attack at the offensive zone and three to four of the forwards will stop their attack and head back to defend another area. Traps in ice hockey are typically used when the defense feels outclassed on offense by their opponent. Pressure created by the trap can slow down their opponent and help predict what their next pass or movement will be. By keeping forwards in the neutral zone there is a higher chance that if the puck does return to them they can easily score or make shots on goal. In general teams will try to keep one forechecker and three to four forwards or players in the neutral zone during a game. The goal is to make the other team's offense feel like they have nowhere to go when "trapped."
Currently no hockey team has a permanent plan to get around a trap that their opponent may play against them during a regulation game. The goal is really for players to see how effectively they can get through it and the easiest one to do this is through the 1-3-1 trap formation. A player must look for any open seam through the defense and once they can get through that it should not be difficult for the rest of the team to break through.
It is unclear who invented the trap in the National Hockey League, but Jacques Lemair is credited with popularizing the system during the 1990s. Lemair led the New Jersey Devils with the system during a game against the Detroit Red Wings in the 1995 Stanley Cup Finals. This move ultimately brought the Devils to victory that night which increased the popularity of the attack throughout the NHL.
A common trap formation is a 1-3-1 which seeks to create some type of a player wall at the centerline, which helps block passes up the boards of the ice and forces opponents inwards. The forechecker's goal during this formation is to seal off passing lanes through the middle and force whichever opponent is carrying the puck towards the boards. A defender should be waiting there in an attempt to retrieve the puck back for his team.
During a neutral trap zone, it is much more difficult for the opponents offense to try and put any shots on goal. Although if an opponent's offender does get through, the goalie is then at risk of being put into a 1 versus 1 situation giving the offender a much higher chance of scoring. The goalie must be focused during a neutral zone trap and not take it as an opportunity to relax because a breakaway may take place.