In 30 seconds
- Japanese for "mistake-proofing".
- Prevent errors by design, or detect them at once.
- In software: type checks, validation, CI gates, safe defaults.
Origins
Shigeo Shingo developed poka-yoke within the Toyota Production System. Classic examples: plugs that only fit one way, or machines that won't start unless a part is positioned correctly.
Software examples
- Strong types that make invalid states impossible
- Form validation that blocks bad input early
- CI pipelines that refuse to merge failing tests
- Confirmation on destructive actions; safe defaults
- Checklists in the Definition of Done
Where you need it
Look at repeated defects or incidents. If the same mistake happens twice, the fix is a design change, not a reminder to be careful. That's the core of poka-yoke.
Myth vs reality
Myth · Poka-yoke means blaming careless people.
Reality · It assumes people make mistakes and designs around it.
Myth · It's expensive.
Reality · Many fixes are small, like a validation rule.
Myth · Tests cover everything.
Reality · Tests detect; poka-yoke also prevents.
FAQ
What are the two types of poka-yoke?
Prevention, which makes errors impossible, and detection, which catches them immediately.
How does it relate to andon?
Poka-yoke catches the problem; andon signals it.
Where should a software team start?
With the most frequent cause of escaped defects.