Skip to content


Poka-Yoke (poe-ka yo-ka) is the Japanese concept of “mistake proofing”. Originialy, Baka-yoke (“idiot-proofing”), the name was changed to be more, um, descriptive.

The classic example is the shift-interlock in a car that prevents the operator from removing they key when the car isn’t in Park.

John Grout has a wiki with all kinds of examples of Poka-Yoke design, including the shape of manhole covers. In fact, Nashua’s manhole covers are the subject of an article that goes into more detail on the geometry of manhole covers than you thought you were going to read today when you woke up this morning.

Certainly in computers we could do with some more Poka-Yoke in our design. Let me posit the notion that for every time the developer blames the user, he didn’t build in enough Poka-Yoke into the system.