How did Toyota's lean production change how the world makes things?

By making only what is needed, only when it is needed, and only in the amount needed. That is the idea of just-in-time, one of the two pillars of the Toyota Production System. Toyota developed this management philosophy and set of practices, and it became the major precursor of what the world now calls lean manufacturing.

The way to run it came from a shop shelf. Taiichi Ohno, who with Eiji Toyoda developed the system between 1948 and 1975, read descriptions of American supermarkets and saw them as the model for the factory. In a supermarket a customer takes goods off the shelf, and the store restocks just enough to fill the space. In a Toyota factory a work-centre would "buy" the parts it needed in the same way, and the earlier station would make only enough to replace what had been withdrawn. The cards that track this are called kanban.

The second pillar is jidoka, or automation with a human touch: stop production when problems occur. Around both sits kaizen, the commitment to improve operations continuously. The main aims are to design out overburden and inconsistency and to eliminate waste.

The idea travelled. After the war the American consultant Deming found Japanese industry far more receptive than American industry had been. In 1980 Fujio Cho explained the Toyota system to an American audience in Detroit. In 1988 John Krafcik coined the term Lean, and Womack and Jones spread it in books.

Some imitations failed. Many Western firms set out to cut inventory directly, without understanding what made the cuts possible, and imitating without understanding may have led to the failure of those projects.