Kanban translates from Japanese as sign board or signal card. It was this signal card that was originally used as a mechanism by car manufacturer Toyota to help them ensure that they received the required car parts just in time. A physical card was sent to the supplier as a signal that the plant needed more of a certain part. The same card was stuck to the part when it was delivered and when the part was consumed, the card, still the same, was detached and sent to the manufacturer again as a signal for the need for more parts. Essential to this process is a rule that the number of cards stays the same. The number of cards cannot be reduced or increased without a formal decision. This mechanism ensures that the number of unused parts are kept at a level that will maximize flow and at the same time minimize manufactured but unused car parts. Car parts that have still not been attached to a car body are considered as waste.

The mechanism is also used in the Imperial Garden in Tokyo. That's where a certain David J Anderson saw the possibility to convert the ideas to software development. This is the story I heard from him: He came to the garden and a guard asked if he had a ticket. Since he didn't have a ticket he got one for free. He was a little confused about it and got even more confused when he, at the exit, was asked to give the ticket back. He later understood that the ticket was a controlling system, making sure the number of people inside the park was under a certain limit. I guess they had found out that if the number of people exceeded this number then the crowd would make people walk on the grass to pass each other and the park would be destroyed. David, who was working at Microsoft at the time, saw similar problems with software development. When people took on too much work in parallel it caused problems like bad quality and late deliveries. Together with the Kanban community, he created the Kanban method that is described in this book.

In this book we will use the definition of Kanban that is described at the Lean Kanban University (http://edu.leankanban.com/).

In this chapter, we will cover the first two days of learning Kanban, and we will learn about Kanban, Agile, Lean, and also the difference between Kanban and Scrum.

Let's begin by looking at the four foundational principles and six core practices of Kanban.