original: the nhl instituted the icing rule on march 13 , 1939 .
simplifications: the nhl instituted the " icing rule " on march 13 , 1939 the nhl instituted the icing rule on march 13 1939 . the nhl instituted the icing rule on march 13 , 1939 . the nhl started the icing rule on march 13 , 1939 . the nhl started the icing rule on march 13 , 1939 . 1 . the nhl established the icing law on march 13 , 1939 . nhl put in the icing rule on march 13 , 1939 . the nhl began using the icing rule on march 13 , 1939 .