Extended 1-3-1 basics
See Defence - 1-3-1 Versoix.
Unlike a 2-3 or 1-2-2 zone, the extended 1-3-1 tries to deny or at least slow down perimeter passes.
X1 is often the baseline runner, fast enough to cover corner to corner. The baseline runner can see the action and coach other defenders.
X3 gets the ball out of the middle, wings X2 and X4 are partners, one puts pressure on the ball when it's on his side (and will stunt and recover), the other defends low weakside in a closed stance (there should always be a defensive triangle protecting the paint).
Option - X3 and X2 trap 1 (on the left side), X5 and X1 are interceptors, X4 protects the basket.
X2 and X3 get in the passing lanes, facing the ball (X1 talks to X2, X5 talks to X3).
X2 pressures the ball if 3 is a shooter, X3 can back off.
X5 covers the high post, baseline runner X1 covers the low post (and has to close out on a pass to the corner), X4 defends weakside (DeChellis - in a closed stance)..
X5 defends dribble penetration, along with X3 and X2 (X2 can stay home if 2 is a shooter).
X3 can help on a pass to the high post, and X5 help on the low post.
On a shot by 1, X3 would sprint to get weakside rebounding position.
X1 has the ball in the corner, taking away baseline.
X5 covers the low post.
X2 denies a pass back out to the wing (a soft trap, facing the ball), or, except on a direct pass (or if too far away), can double-team with X1 (e.g. if 2 is a shooter, or to discourage a skip pass to 3).
X3 has the high post and distorts a skip pass to 3.
X4 protects weakside, and has a skip pass to 3.
On a shot by 2, X2 would sprint inside to get middle rebounding position. If there is no high post, X3 gets weakside rebounding position.
On a pass back to 1, X2 would push the ball out if it's too close to the basket, X3 gets in the passing lane to 3.
On ball reversal to 3, if there is an attacker in the corner, X4 comes out wide in the passing lane, and pushes the ball out if it's too close, helping X2 sprint to cover low weakside.
If 2 is a shooter, X4 can push the ball out but not as aggressively for a shorter run to trap in the corner.