A pokayoke is a device or method on the factory floor that prevents mistakes. The word is said to come from poka, a careless error, and yokeru, to avoid. It is used abroad as well.
A factory management magazine credits these methods to Shingo Shigeo, a consultant who improved many factories after the war and who is said to have shaped the origins of the Toyota Production System. It notes that a pokayoke is built cheaply, with ingenuity instead of money.