Can a poka-yoke device be part of a jidoka system?

Yes, very commonly. Jidoka needs a detection mechanism as its first step, and a poka-yoke sensor or limit switch — one built to detect a specific physical condition, like a part not seated or a fastener not present — is often exactly what triggers the automatic stop. In that setup the poka-yoke device is doing the "detect" half of jidoka's detect-and-stop sequence.

Does jidoka mean every machine has an automatic shutoff?

Not necessarily automatic in the sense of no human involvement — jidoka literally translates closer to "automation with a human touch." Some jidoka implementations are fully automatic (a sensor trips a machine stop), while others rely on a worker recognizing an abnormality and pulling an andon cord themselves. Either way, the defining feature is that the process stops the moment something is wrong, rather than continuing to run and letting a supervisor or downstream inspection catch it later.

Is poka-yoke only for manufacturing assembly?

No. The principle — make the wrong action physically or procedurally impossible — shows up anywhere a process has a discrete failure mode with a clear physical or structural fix: a gas cap that won't let you drive off with the pump nozzle still attached, a software form that won't submit with a required field blank, a medical connector standard (like ISO 80369) designed so an IV line and a feeding tube physically can't be cross-connected.

Which one should a team build first, poka-yoke or jidoka?

In practice teams often build jidoka-style detection first, because it's usually faster to add a sensor and a stop condition than to redesign a part or fixture. But the more durable fix is almost always poka-yoke, because it removes the failure mode entirely rather than catching it every cycle. A common improvement pattern is: use jidoka to stop the line and study the abnormality, then design a poka-yoke device so that specific abnormality can't recur — turning a recurring jidoka stop into something that never needs to be caught again.

Does a jidoka stop always mean a defective part was produced?

No. Jidoka triggers on an abnormality — a condition outside the expected range — not exclusively on a confirmed defect. A torque reading slightly under threshold, a cycle time that ran long, or a part that failed to seat correctly can all trigger a stop before any bad part is actually completed. That's part of the point: jidoka is often catching the precursor to a defect, not just the defect itself, which is what makes "immediately after" still fast enough to prevent the defect from ever fully forming or shipping.

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Concept Explainer · Industrial & Systems

Poka-Yoke vs. Jidoka

Both stop defects. The difference is when — poka-yoke stops a defect from ever existing, jidoka stops one that already happened from going anywhere.

It's common to hear poka-yoke and jidoka lumped together as "the two Toyota tools for catching errors." That flattens a real distinction that matters for how you design a process. Poka-yoke ("mistake-proofing") is a design-level intervention: a part, fixture, or connector shaped so the wrong action is physically impossible to take in the first place. Jidoka ("automation with a human touch," sometimes translated "autonomation") is a detection-and-response principle: a machine or worker watches for an abnormality, and when one shows up, the process stops itself — immediately, before the defect can travel to the next station. One makes the error impossible. The other makes the error impossible to ignore or pass on. They usually work together, but they are not the same lever.