A means of shutting down a production process at the moment a defect or problem occurs. 

In the case of an automatic line, sensors and switches should usually be installed here that automatically stop the line as soon as a deviation is detected. In the case of a manually operated line, a stopping system is often installed at a fixed position. Operators then have the option of pulling a cord above their heads or pressing a button that stops the process at the end of a work cycle if the detected problem cannot be fixed during the cycle. 

These examples illustrate the jidoka principle, which prevents defects from moving to the next process step, and prevents the production of a series of defective items. Mass producers, on the contrary, will try to avoid stops as much as possible to achieve high utilization of their equipment, even when known defects occur repeatedly and require repair work at the end of the process.