The kanban was then the final piece in the jigsaw. One of the major benefits of kanban is that it is very simple; it is also quite visible to all concerned and its logic is clear. It worked when all the issues preventing immediate response had been addressed and was the mechanism by which a build up of stock could be prevented. The yellow card attached to the container, or the floor space between two work benches, was the signal to initiate production of more of the item. If the assembly line stopped, then the subassemblies ceased being used and no more signals were generated. This contrasted markedly with the position in Western plants where an assembly line problem quickly led to a massive pile-up of inventory with items being mislaid and damaged.

Few of the Japanese ideas for change in manufacturing were totally new. Frederick Taylor and Henry Ford had promoted many of them at the start of the 20th century. Where the Japanese did have much to teach us was in the total commitment of everybody to these new ways of working. We began to hear of stock levels being reduced to the point that every slightest problem immediately caused a major hold up, and this was actually treated as a reason for celebration. «A problem is a pearl, «we heard, meaning that finding a problem in a process was a good thing. Why? Because the problem was there and we didn’t know about it, but now we do, so we can fix it.

As we understood more of JIT we learned that stock levels and lead times were not the only targets of the Toyota Production System and its followers in Japanese industry. We began to realise that our aim must be to eliminate waste in all its forms. «What is waste?» we asked ourselves, and turned to people like Mr Ohno and Mr Shingo and were told that «waste is anything which does not add value.»

We knew already of some wastes – for example, inspection adds no value. Why not just get the process right and then we needn’t carry out this activity? Similarly, why expedite our suppliers when, if we had chosen good partners and had a true partnership with them, this would not be needed? Why move items to a dedicated packing area if we could perform the packing in tandem with the assembly operation for the product and eliminate this movement? Why move parts from one end of a factory to another, and back again, if a little more thought in laying out the plant differently might take out this activity?

So, JIT became Lean when it was recognised that parts arriving only when required and only in the quantities required is only a part of the story.