A shooter is pinned down from the block, comes up off that screen, and runs straight into a dribble handoff from the player holding the ball at the top. Two screens, one after the other, with no pass in between.
Why coaches use it
The value is in the sequence. The first screen makes the shooter’s defender fight up the floor. The second one arrives immediately, and a defender who is already trailing has no chance to get back in front.
Because the second screen is a handoff, the shooter catches the ball with a live dribble and momentum, rather than standing still. That is the difference between a contested catch-and-shoot and a drive with a defender behind you.
It also gives your big something to do that is not posting up. He holds the ball at the top, delivers the handoff, and turns into the ball screen behind it if nothing came of the first two actions.
Zoom and Chicago are the two names you will hear, and most staffs use them for the same thing. Some reserve Chicago for the version run out of a 5-out delay alignment, with the big holding the ball at the top. Our library play uses that name for exactly that version.
How it is guarded
The shooter’s defender has two screens to survive. Chasing over both takes the shot away and gives up the drive. Top-locking the first screen stops the whole action, and the standard counter is a back cut to the rim.
Switching is common and cheap, but a switch on the handoff usually leaves a big on a guard in space, which is the shot the offense will take.