# Kanban System

Kanban system is one of the method of Inventory Control . It is famous because Toyota uses.

It is different from Reordering Point System .

## Basic Idea

In this system, the amount of reordering is decided the amount of each ship in ideal. In the ideal, inventory could be 0.

But inventory is not 0 in the real, because lead time and minimum reordring amout are needed.

## Kanban

One kanban is the unit of the reordring amout. If the amount of ship reaches this unit, reordring starts.

In this system, the sum of the amount of inventories and the amount under reordering is not so changed.

## Calculation Number of Kanban

Famous way to decide the number of kanban is similar to reordering point system using normal distribution . In this way, the difficuty to use normal distrubution appears in the same way.

Reordering Point System uses "maximum value of the amount of the ship in lead time". This value is also used to calculate the number of kanban.

The number is "maximum value of the amount of the ship in lead time" / "minimum reordering unit" + 1