Poka-yoke or Mistake Proofing

pokayoke
Poka Yoke Illustration

Poka Yoke Illustration

 

What is Poka-yoke?

 

Poka-yoke (poh-kah yoh-keh) was coined in Japan during the 1960s by Shigeo Shingo who was one of the industrial engineers at Toyota. Shigeo Shingo is also credited with creating and formalizing Zero Quality Control (poka-yoke techniques to correct possible defects + source inspection to prevent defects equals zero quality control).

The initial term was baka-yoke, which means ‘fool-proofing’. In 1963, a worker at Arakawa Body Company refused to use baka-yoke mechanisms in her work area, because of the term’s dishonorable and offensive connotation. Hence, the term was changed to poka-yoke, which means ‘mistake-proofing’ or more literally avoiding (yokeru) inadvertent errors (poka). Ideally, poka-yokes ensure that proper conditions exist before actually executing a process step, preventing defects from occurring in the first place. Where this is not possible, poka-yokes perform a detective function, eliminating defects in the process as early as possible.