What is the name often used to refer to the fierce rivalry between the Montreal Canadiens and the Boston Bruins?

The fierce rivalry between the Montreal Canadiens and the Boston Bruins is often referred to as "The Original 6 Rivalry." This nickname stems from the fact that both teams were founding members of the Original Six era in the National Hockey League (NHL), which comprised the six teams that existed from 1942 until the NHL's expansion in 1967. The intense competition and storied history between these two franchises, which include numerous playoff encounters and memorable moments, have solidified their rivalry in the hearts of hockey fans.

The other terms provided do not accurately capture the essence of this particular rivalry. "The Battle of Canada" generally refers to matchups involving Canadian teams rather than a specific rivalry between teams from different cities. "The Eastern Conference Clash" could apply to various matches between Eastern Conference teams, lacking the specific historical context. "The Maple Leaf Showdown" conveys a rivalry involving the Toronto Maple Leafs, which is separate from the Canadiens and Bruins. Thus, "The Original 6 Rivalry" is the most precise and historically grounded term for what exists between the Canadiens and the Bruins.