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.