Just-In-Time is a critical Lean tool; in fact, it is one of the two pillars of the Toyota Production system, the other one being Jidoka. The Just-In-Time (JIT) manufacturing system is a planning system for manufacturing processes that minimizes the availability of material inventories at the manufacturing site to only what, when, and how much is strictly necessary. The Just-In-Time (JIT) system is an integrated set of activities designed to achieve high-volume production using minimal inventories; raw materials, work-in-process, ?nished goods, and other consumable goods.