Jidoka means building the detection of abnormality into the process, so it stops itself instead of producing defects until someone notices. The usual translation, “automation with a human touch”, obscures the idea more than it conveys it.
It comes from Toyoda’s automatic loom, which halted when a thread broke. Before that a loom with a broken thread carried on weaving flawed cloth, so one person watched one loom. Afterwards one person could watch many. That economic argument is still the whole case: separating human work from machine work only becomes possible once the machine can be trusted to stop.
It sits next to Poka Yoke and gets confused with it. Poka Yoke prevents the error being made at all; jidoka catches the abnormality once it has occurred and halts. Prevention at the step versus detection at the system.
Both depend on stopping being genuinely permitted. In an organisation measured only on output, the stop gets overridden, and the mechanism is dead in practice long before anyone acknowledges it. Detection thresholds fail the same way from either direction — too loose and nothing ever triggers, too tight and the alarm becomes background noise.
