James King

I will let you decide how much of this history is accurate, but it seems right to me.

Once there was a guru at a car company who noticed that people were making errors.

He decided that he could tell them not to make mistakes any more, but that errors would still happen.

The team said “Ohno, this has got to stop”, so Taiichi, as they also called him, came up with a structured approach to predicting and removing mistakes before they happened.

He called his new approach Baka-Yoke.

In Japanese, 「バカよけ / バカ避け」 (baka-yoke) literally means “idiot-proofing” or “foolproofing” (making something so even a “baka” can’t mess it up).

You could say “Hey you Baka, do not mess this up.” But the approach did not seem to work as well as it potentially could.

As soon as people made something Baka proof, Bakas would evolve to be even bigger idiots. No matter how hard people tried, some idiot could still mess things up.

So Ohno changed the name from Baka-yoka to Poka-Yoka.

Ppoka-yoke (ポカヨケ), usually translated as “mistake-proofing”, which sounds more polite than “idiot proofing” because we are making the system safer rather than calling people idiots.

But it was not about good manners or being nice to people. The change in thinking. Rather than anticipating every single possible mistake any idiot could make, we now align mistake proofing to the user/builder of the system.

We protect the competent user or target user from predictable mistakes, but we also choose to either train them to a level of competence that makes mistakes unlikely or we decide when to stop idiot proofing things and make it safe to fail instead.

So an idiot fails once and breaks everything but a competent user is both able to rely on our system (through poka-yoke) and able to safely learn from mistakes to be stronger and better in the future.

Thus we continuously improve our systems and continually learn and grow as people.

Anyway, that’s the way it was explained to me.