Toyota pioneered the just-in-time inventory system through the Toyota Production System. The central idea was to make only what is needed, when it is needed, and in the quantity needed.
Toyota’s approach developed in postwar Japan, when the company faced scarce capital, limited factory space, and weak demand compared with mass-production rivals in the United States. Kiichiro Toyoda originated the just-in-time concept, while engineer Taiichi Ohno and executive Eiji Toyoda helped develop it into a broader production system.
Ohno drew inspiration from American supermarkets: a store replenishes shelves as customers take products away. In a Toyota factory, downstream workstations pull only the parts they require, while suppliers and preceding stations replenish that exact amount. This reduced excess inventory and exposed production problems instead of hiding them in stockpiles.
Just-in-time is one pillar of the Toyota Production System; the other is jidoka, often translated as automation with a human touch. Toyota’s methods later influenced lean manufacturing worldwide, but simply cutting inventory without Toyota’s quality controls and problem-solving discipline can create shortages rather than efficiency.