The blue ice where the goalie plies his trade, 6 feet wide and 4 feet in length plus a 2-foot semi-circle in front of the net. This is primarily the goaltender's area where rules sometimes prohibit goals being scored if offensive players are in the crease when the puck enters the net.
The crease dimensions and colors in the National Hockey League - NHL have transformed over the years, as well as the rules guiding both what offensive and defensive players can do in the specially designated area in front of the goal.
One of the rules prohibits defensive players from gathering, grabbing or covering the puck, or else the referee can award a penalty shot to the non-offending team. Other rules include strict and more severe punishment for running into the goaltender or checking another player into the net from behind.
One of the most bizarre years in league history occurred in 1998-99 when a rule was enforced by video review that if an offensive player had any part of their skate in the crease, a goal would be disallowed. The rule, only in affect for the one season, disallowed dozens of goals throughout the year in both the regular season and playoffs.
However, the final goal of the playoffs by Brett Hull, which clinched the Stanley Cup for the Dallas Stars, was questioned by the Buffalo Sabres when replays showed Hull had his own foot in the crease when he scored on the rebound goal.