<P> The 1951 through 1953 playoffs changed the division finals into a best - of - five playoff . With only nine league members in 1953 -- 54 , the NBA cut its postseason tournament field from eight teams to six ( from 1954 through 1966 , the period of eight to nine league members ) . Round robins were played in 1954 , uniquely in NBA history -- a three - team round robin among the three playoff teams in each division . From 1955 to 1966 , the first - place team in each division was idle while its two runners - up faced played a best - of - three . Division finals were expanded to best - of - seven in 1958 and division semifinals to best - of - five in 1961 . </P>
<P> The 1951 through 1953 playoffs changed the division finals into a best - of - five playoff . With only nine league members in 1953 -- 54 , the NBA cut its postseason tournament field from eight teams to six ( from 1954 through 1966 , the period of eight to nine league members ) . Round robins were played in 1954 , uniquely in NBA history -- a three - team round robin among the three playoff teams in each division . From 1955 to 1966 , the first - place team in each division was idle while its two runners - up faced played a best - of - three . Division finals were expanded to best - of - seven in 1958 and division semifinals to best - of - five in 1961 . </P>
when did the nba start best of 7
when did the nba start best of 7
1958
1958