Setting Up
Line everyone up in a simple vertical stack on the ball-side edge of the key. Put your best three-point shooter at the bottom of the stack and a post capable of a short midrange shot one spot above him.
Clearing the Gap
The bottom of the stack cuts immediately to the corner, calling loudly for the ball the whole way to drag the low wing defender out with him. At the same time, the middle player of the stack steps toward the middle of the key and screens the zone's middle defender.
The top of the stack clears all the way out to the top of the key — both to drag the top defender away and to stay in a safe position defensively.
Stepping Into the Gap
With the low wing defender pulled to the corner and the middle defender screened, a clean gap opens in the middle of the key. The remaining post steps into it, hands ready, and catches the pass for an immediate midrange shot — there's no time to take a dribble or bring the ball down.
If the low wing defender manages to stay home and cut off that pass instead, the shooter is left open in the corner for the three.
Coaching Points
Timing decides everything: the post stepping into the gap has to wait for it to actually open before calling for the ball.
That post needs both hands up and ready the instant he steps in — there isn't enough time in this play for a dribble or a low pickup.
The corner cutter must call loudly the entire way; a silent cut doesn't drag the defender the way a loud one does.