Toyota Production System: Beyond Large-Scale Production

Ohno developed the Toyota Production System over decades as a Toyota executive and wrote this short book as a first-hand account of what he built and why. It is the primary source for the ideas that later became lean manufacturing.

The system rests on two pillars. Just-in-time means producing only what is needed, when it is needed, in the quantity needed, coordinated by the kanban signal that pulls production from downstream rather than pushing it from a schedule. Jidoka, which Ohno translates as automation with a human touch, means a machine or a line stops automatically when a defect occurs, so that problems are surfaced immediately rather than passed downstream and so that one worker can supervise several machines.

Ohno is explicit that the purpose is the elimination of waste, and he defines seven types: overproduction, waiting, transport, over-processing, inventory, motion and defects. Overproduction is the worst because it conceals every other waste. He also states the five whys method for root cause analysis, and he is clear that reducing inventory is valuable because it removes the buffer that hides problems, not because inventory itself is expensive.

The book is short, discursive and occasionally repetitive, and it assumes a manufacturing context. Ohno's account of his own reasoning includes the influence of American supermarkets on the pull concept and of Ford's flow ideas. Readers should note that the system took Toyota roughly thirty years to build and that most attempts to copy it have installed the visible tools without the problem-solving discipline that the tools exist to enable.