Stick work is a big part of the NHL, but what's the difference between legal and illegal play? A slashing penalty can drive fans and players crazy, as it may be the hardest one to hold at a common standard. However, the NHL Rulebook can help us get a good idea of the penalty.
The rulebook states that "Slashing is the act of a player swinging his stick at an opponent, whether contact is made or not. Non-aggressive stick contact to the pant or front of the shin pads, should not be penalized as slashing. Any forceful or powerful chop with the stick on an opponent’s body, the opponent’s stick, or on or near the opponent’s hands that, in the judgment of the Referee, is not an attempt to play the puck, shall be penalized as slashing."
The most common penalty is a minor one, which is two minutes for a penalty that doesn't attempt to injure or injure an opponent. The major penalty is used if the slash does injure an opponent, and a match penalty is assessed if the referee deems the contact to be made to deliberately injure.
Above are examples of the two different types of injuries. Joel Edmundson received a minor penalty for his slash on Jonathan Marchessault. It was a basic infraction that made contact on the arms. The subban penalty was more deliberate and caused an injury to Stone.