The Japanese-derived term for producing exactly what is needed, when it is needed, is just-in-time.
Usually abbreviated JIT, just-in-time is an inventory and production approach designed to make or receive goods close to the moment they are required. By limiting excess stock, it reduces storage costs, overproduction, tied-up capital, and waste.
The approach became closely associated with Toyota's postwar production system. Taiichi Ohno drew inspiration from supermarkets: a customer takes products from a shelf, and the store replenishes only what has been removed. In manufacturing, downstream work centers similarly request parts from upstream processes, creating a pull system.
JIT is not the same as kanban, kaizen, or poka-yoke. Kanban is a signaling tool often used to control pull-based replenishment; kaizen means continuous improvement; and poka-yoke refers to mistake-proofing. JIT can improve efficiency, but very low inventory also leaves operations more exposed to supplier delays, defects, disasters, or transport disruptions.