TPS & Jidoka, interview of Tomo “Tom” Harada by Art Smalley:
So when Mr. Ohno came to the automotive company after WWII and saw one man operating one machine tool he thought that it was strange and inefficient. He embarked upon a path of breaking down the notion of one man one machine in the engine shops. Instead of “monitoring” machines the operator was to walk between two machine tools and keep them both up and running. Then three machines and four machines and so on.