Line defense is a strategy used in basketball. It is referred to as the "line defense" because of its formation on the court, which consists of two lines of defense. Three players at the front of the defense and two players behind . The line was the first zone concept to be used in basketball. The line defense was developed to counter the fast break plays that were being developed, and adopted, at the time. The line defense was the catalyst of the future 3-2 zone defense.