Pull is the architecture for continuous improvement
Seventeen years ago, when I first saw a Toyota sensei come to a supplier, he went to a workstation in front of the assembled executive group, and watched the operator work for about ten minutes, before moving a box of components closer the operator’s hand. Then the sensei went to the meeting room and drew a simple diagram of the river and the rocks (translated by his interpreter) and… left. At the time, the execs where furious – they had been asked to come to the plant for this?
That was the most powerful message we ever got about lean, and Toyota worked for several years with this supplier to teach it how to improve the cells (kaizen) and how to pull (just-in-time). It took us many years to understand ‘the river and the rocks”: the pull system shows you where your problems are so that you can do kaizen effectively – in a way that pays at budget level. Furthermore, with pull, everyone can see the problems, so when local supervisors have the right attitude, they will, by themselves, focus on the right kaizen opportunities and solve the problem…