 The NHL changed its divisional alignment and playoff formats numerous times as it grew . The league 's doubling in 1967 also led to the expansion of the playoffs to eight teams from four the previous year . Expansion to 18 teams in 1974 caused the league to realign into two conferences and four divisions , each named after important figures in league history . The teams were split into the Campbell Conference , consisting of the Patrick and Smythe divisions , and the Prince of Wales Conference , consisting of the Adams and Norris divisions . The playoffs were expanded to 12 teams , and each division winner was granted a bye in the first round of the playoffs . The addition of the four WHA teams in 1979 saw the playoffs expanded to 16 teams . Finally , in 1981 , the league realigned all teams by geography . Eastern teams played in the Adams and Patrick divisions of the Wales Conference , and Western teams played in the Norris and Smythe divisions of the Campbell Conference . In addition , the playoff format was changed to have the top four teams in each division qualify rather than the top 16 teams overall . The first two playoff rounds were played entirely within each division . This format lasted until 1993 . 
