In the late 1940s, Toyota found a better engineering process from an unlikely source: the supermarket. They noticed that store clerks restocked a grocery item by their store’s inventory, not their vendor’s supply.

Only when an item was near sellout did the clerks order more. The grocers’ “just-in-time” delivery process sparked Toyota engineers to rethink their methods and pioneer a new approach—a Kanban system—that would match inventory with demand and achieve higher levels of quality and throughput.

So how’d they do all that?