The NHL is a copycat league. Most teams implement deviations of similar systems in all three zones – variants of different formations that a team takes up based on score, pressure, momentum, urgency, and other factors that determine the outcomes of a hockey game.
At even strength, most clubs change up between a 2-1-2 or a 1-2-2 in the offensive zone, ramping up pressure with the former and staying a little more passive with the latter, depending on game circumstances. A 1-2-2 formation in the neutral zone has given way to a more defensive 1-3-1 to bog down the opponent’s attempt to speed through the center of the ice and enter the offensive zone with authority.