Database Resources. NBA Statistics and Analysis. NBA Basketball on TeamRankings.com. NBA & ABA Basketball Statistics & History. NBA Rules History. Take a look back at some of the rules changes that have taken place over the years.
(Changes/clarifications implemented prior to season, except where noted) Initial Rules • 60-game schedule followed by championship playoffs involving the top three teams in each division. • Games are 48 minutes long. • Players are allowed six personal fouls. • Every time you scored, the other team is given possession of the ball. • Zone defenses are allowed. 1946-47 • Zone defenses outlawed on January 11, 1947.