Butterfly style
In ice hockey, "butterfly style" is a technique of goaltending distinguished by the goaltender guarding the lower part of the net by dropping to the knees to block attempts to score. The butterfly style derives its name from the resemblance of the spread goal pads and hands to a butterfly's wings. The butterfly style is contrasted with stand-up style, where most shots on a goal are stopped with the goaltender on his or her feet. Many factors helped make it a de facto standard style of play today, including the invention of the goalie mask by Jacques Plante, Vladislav Tretiak's outstanding use of the style at the 1972 Canada–USSR Summit Series, the National Hockey League (NHL) emergence of Tony Esposito in the 1970s and Patrick Roy in the 1980s, the development of lightweight materials for pads and the influence of professional goaltending coaches such as Warren Strelow, Benoit and François Allaire. There are few who exclusively employ a stand-up style in the NHL.