Used oftentimes when a team is trailing and time is running out on them, the 2-2-1 full-court press is an aggressive, full-court defense used to pressure the offensive team into committing quick turnovers. It is also often used by teams who want to create a helter-skelter like tempo, with a frantic pace at both ends of the court. Can be very successful when used against a team without a good point guard, whose lack of ball-handling skill can cause him to lose the ball time and time again.
How to play the 2-2-1
Place two defenders at the near baseline (where the ball is being inbounded), about five feet to each side of the basket. Place two defenders just inside half-court, the one on the strong side nearer the sideline, the defender on the weakside inching his way towards the middle. The final defender is the safety valve; usually the team's center, who can offer a last stand of resistance if the front four players on beaten.
When the ball is inbounded to a side, the front player on that side forces him to the sideline, and the player at halfcourt comes up and traps the man with the ball. The weakside baseline player moves to cover the return pass from the man who inbounded it, therefore, creating no safety valve for the player who is trapped.
The weakside defensive player at half-court moves up to the middle, to discourage a pass towards the middle of the floor. If everything goes as desired, the player with the ball will make a poor decision and turn it over. If the offensive player does find somebody to pass to, then the players shift to the ball, and attempt to set up another trap with similar defensive assignments.
They attempt to force the ball to the corners, trap, and cover the middle of the floor. Do not let the player advance the ball on the dribble. A cardinal sin in this defense is to let a player split the trap with the dribble. This destroys the heart of the defense, and will most likely lead to a high-percentage shot on the other end. The 2-2-1 adheres to the same philosophy that the 2-3 zone does, in that players are responsible for given areas. The difference is that the players are expected to be much more aggressive in this set-up, and are expected (naturally) to cover larger areas on the floor.