Whenever I read articles or twitter comments about Kanban in Software Development, I have the feeling that most authors do not understand the topic about  they write.

The famous Kanban system of Toyota was inspired by the way supermarkets supply their customers. “At Toyota, when a process goes to the preceding process to retrieve parts, it uses a kanban to communicate what parts have been used.” [1]. In the beginning it was the box “shopping card” that the post-process person used to communicate how much goods he needs from the preceding process. Later this was optimized by the idea of the one-piece flow. So the box was reduced so it could only hold one piece.

People argue now, that this indicates a flow. Well in fact it is not a flow. It is an iteration! A rhythm, a beat. At every beat some part gets delivered (maybe only one). A beat is a distinct moment in time, separated by a pause. So it is not a “flow”. A series of beats creates a rhythm. In martial arts it also looks always like a flow, but in fact between every “beat” is a pause. So again it is not a flow. It is a continuous stream of beats. Better comparable with a dance than with a water flow.

We are humans. Humans are used to rhythms, people needs rhythms. You can see it everywhere. In music, in arts, in live, in our heart beat.

So iterations are the core element of continuity. Flow does only exists as a phenomenon in the non-biology nature. The old principle natura non facit saltus [2] (nature does not make jumps, ) is wrong as we know from quantum physics. [2, 3]

Bibliography:

• [1] http://www2.toyota.co.jp/en/vision/production_system/just.html
• [2] “However, as the basic structure of DNA is discrete, nature is now widely understood to make jumps at the biological level, if only on a very small scale.” http://en.wikipedia.org/wiki/Natura_non_facit_saltus
• [3] http://www.thefreedictionary.com/quantum+jump