The Force

The force is a concept used by the vast majority of defenses to simplify the job of cutter defenders by leveraging the mark to give downfield defenders a section of the field to prioritize and focus on defending. The mark is an extremely important and impactful position. By being the only player that can stand close to the player with the disc, they can effectively stop all easy throws to the space behind them. However it is unrealistic to expect the mark to block all throws or even all throws downfield. Therefore to maximize the effectiveness of the mark and downfield defenders, teams will designate a side of the thrower to stop, blocking forward throws of a certain type (either backhand or forehand) and relying on downfield defenders to stop throws on the unmarked side. The video below explains the concept: