It's not complicated, really, to explain the Islanders' rapid transformation from the league's worst defense to the best.
Xs and Os play a part, for sure, as opposing offenses find little ice to operate through the Isles' tight formation near their crease, keeping opponents to the outside and limiting both cross-ice passes and rebound chances. That foundation has put them in strong position to make the playoffs for the first time since 2016.
But if it were that easy, Doug Weight might still be coaching them instead of Barry Trotz, who along with new President/General Manager Lou Lamoriello, had proclaimed that the porous defense that allowed the most goals per game (3.