The Toyota production system was partly inspired by the idea of the American supermarket. Let me take you back one step and explain how the Toyota production system works. The two pillars of this system are “Just-in-time” and “Auto-activation”. The Just in time production means that the workstation or the plant produces what is needed, at the time needed with the quantity required to eliminate the waste of over production and inventory handling. The just in time concept is applied using a “Kanban card”. A Kanban is a means of communication between the work stations where the latter work station send a card to the former station stating the product needed, the quantity needed and when is it needed.
A Kanban Card
The former station shouldn’t produce any parts unless it receives a Kanban from the latter station thus avoiding over production and inventory handling costs. Now, let me explain to you how this system was inspired by the American super market. After World War II Japan was overwhelmed with the American economy and culture. And the Hypermarket concept started to take its place in the Japanese economy.
Taichi Ohno, in his book “The Bible of the Toyota production system” describes the relation between the super market and their production system. He begins by explaining the fact that in a super market the customer purchases what he needs, the quantity he needs when he needs it. Now let’s compare this purchasing activity to the Toyota production system. The customer here is the latter process which goes to the super market which is the earlier process to get the “parts” he needs in the amount he needs when he needs.
In 1953, this system was actually applied in the machine shop of the main plant. Despite the fact that the system eliminates the waste of over production and inventory handling costs, a confusion arises if the latter process require a huge amount of parts in a short time due to market needs fluctuations. The optimum practice in this case is averaging the production. Average production has its merits because it aids in stabilizing work force levels, output, and production schedules.