Shutting down a machine improves productivity in a gemba kaizen environment because

(a) the machine is shut down when it is replaced by a newer, better machine.

(b) shutting down a machine when there is any defect, then investigating the cause, leads to permanent preventative action so that that problem doesn’t happen again.

(c) the machine has to be shut down, because any worker who makes a mistake is fired, and there is no one to run the machine until he is replaced.

(d) when the manager plays a prank by shutting down a machine, it increases worker morale.