Japanese expression for “mistake-proofing/avoidance”. In the context of lean manufacturing, poka-yoke is a principle implemented to avoid defects during production. Machines and processes are designed in such a way that only a correct part can be produced. The process stops immediately if poka yoke-proofing devices do not release the process. Product poka yoke requires form fitting of the part in the tool, while process poka yoke requires activation of sensors or testing devices.