The current system...: For the 1986-87 season, the eight first-round series were changed from best-of-five to best-of-seven games, meaning it takes 16 victories to raise the Stanley Cup. In 1993-94, however, there was a slight change that remains today. Thats when the postseason became conference-based, rather than division-based. As a result, after the three division winners take the conferences top seeds, the five remaining clubs are ranked by how they finished in the East or West, not in their division.
In the 1970s...: When the league featured 18 teams, 12 made the playoffs and the top four received a first-round bye. Those who had to play first-round series, just had to win a quick best-of-three set. When the league expanded to 21 teams, 16 made the tournament like today. But the teams were ranked 1-16 overall back then. That created the possibility two teams from the same division or region could end up in the Stanley Cup final. For instance, in 1979-80, the Islanders and Flyers, division rivals today, met for the title. Imagine the Lightning meeting the Panthers for the Cup.
In the 1960s...: The league doubled from six to 12 teams. Finally, there were enough clubs to make two divisions of six (East and West). The top four from each division advanced to the tournament. And all series were best-of-seven.
In the 1950s...: The Original Six: Canadiens, Maple Leafs, Bruins, Rangers, Blackhawks and Red Wings. The top four made the postseason. All series were best-of-seven.
Compiled by Tim Sullivan