With the rate of goals per game increasing, NHL owners took action. A tweak was made to the forward passing rule by adding the following clause, "no attacking player allowed to precede the play when entering the opposing defensive zone." If this sounds familiar, you are most likely thinking of the offside rule.
In 1930-31, the structure of the offside rule continued to evolve. Those in command decided the puck should first enter the offensive zone prior to any player. The implications are two-fold. First, the clear wording left little room for interpretation. Second, the rule influenced a new style of play. Adapting to the rule, teams could now employ an offensive strategy which included the "dump & chase" and "shoot-in". The intention was to concentrate on puck pursuit and pressuring the opponents defensive core. Other aspects of the game would be affected, such as concepts for backchecking and forechecking.
Then, there are other rule changes that are cosmetic, but have the intended impact.
In January 1941, the NHL altered the rule for those engaging in fisticuffs. Players embroiled in a fight wouldn't suffer a financial penalty, but any player joining in on the mayhem would be fined $25. It didn't take long for the league to witness how this rule would work under game conditions. In a contest played on January 16, 1941, Boston's Milt Schmidt and New York's Art Coulter dropped the gloves and duked-it-out. For a moment, think back to all the vintage footage relating to this period of time. If two players started whaling on each other, it would only be seconds before the old film showed others joining in on the fracas.
The threat of financial retribution made players think twice prior to just leaping in. The amount of $25., provides some correlation with salaries being paid out. A player and his family couldn't afford to relinquish this sum every time a scrap broke out on the ice. In New York, Schmidt and Coulter were the lone combatants. As newspaper report put it, "Coulter and Schmidt squared off while their mates acted as interested spectators."