Zone defences are classified by the alignment of the players from the front line to the back. For example a 1-3-1 zone would have one player at the front, or point position usually about the top of the keyway. Three players would line up in the next line with one in the middle of the free throw line and the other two on the wings The player in the back line starts just in front of the basket.
Different zone alignments have different strengths and weaknesses. When selecting the type of zone defence you want to use, there should be a good understanding of your players and your opponents. The 1-3-1 zone has strength around the middle and key area, but may be vulnerable in the corners and low post area especially if the opponents are good perimeter shooters.
In diagram 1 the 5 player is usually the tallest player and strongest rebounder. 2 and 4 are usually the tallest forwards and should also be good rebounders, 1 is usually the point guard, who dictates which side of the court the offence should be forced to play. 3 must be active as he is likely to be required to move quickly from one side of the court to the other to apply pressure and he should also be capable to defend taller players close to the basket. The baseline player in the 1-3-1 zone defence has the most difficult task.
Some coaches will use the 1-3-1 zone defence to set up double team opportunities particularly when a pass is made to a man in the corner (See diagram 2). 3 applies pressure on the pass receiver and 2 drops down to set a double team. In this case 1 must try to anticipate and prevent an outlet pass. 5 must deny any pass into the low post, or medium post area, while 2 has to anticipate a cross court pass where either of two players could be available. Usually the gamble of the double team is acceptable as it requires considerable composure and skill for a player who is double teamed to make a successful cross court pass. If 1 is unable to deny an outlet pass by the man being double teamed in the corner he must at least apply quick pressure on the receiver to prevent him from passing quickly to a team mate on the other side of the floor. If this does happen 3 must release from his man quickly and adjust to be able to cover the next pass that may well be made to a man in the opposite corner.