Where jidoka comes from
Sakichi Toyoda's automatic loom of the 1890s stopped itself when a thread broke, so one operator could watch many looms and no defective cloth was woven. That principle, a machine that detects its own abnormality and stops, became jidoka, and later extended to people: an operator who sees a problem stops the line.
The four steps of jidoka
- Detect the abnormality. A sensor, a gauge, a visual check or an operator's judgement.
- Stop. The machine or the line halts, or the operator pulls the andon cord.
- Fix or correct the immediate condition. The team leader responds and the problem is contained.
- Investigate the root cause and install a countermeasure, so the abnormality does not recur.
The first three steps protect the customer today; the fourth is where improvement happens.
Why stopping is worth it
Stopping a line is expensive, which is the point: it makes problems impossible to ignore. A line that never stops is either perfect or hiding defects in inventory and rework. Over time, jidoka reduces stops because each one removes a cause.
Jidoka in practice
- Andon: the cord, light and board through which a stop is signalled and answered.
- Poka-yoke: devices that detect or prevent the error so the stop happens at the right moment.
- Standard work: the definition of normal, without which abnormal cannot be seen.
- Separating people from machines: once a machine can stop itself, the operator does not need to watch it and can do other work.
Jidoka and daily management
Yesterday's stops are a standing item for the Tier 1 huddle: how many, where, why, and which recur. Chronic causes go into structured problem solving, and the countermeasure is verified when the stops cease. Jidoka without that review becomes a list of interruptions rather than a source of improvement.
Common misunderstandings
- That jidoka means automation. The machine stopping is the means; built-in quality is the point.
- That people will be blamed for stopping the line. If they are, they stop stopping, and defects flow again.