Still processing the impressions of DeVoxx 2009 in Antwerp. One of the most interesting sessions for me was the university talk about Kanban in Action by Olav Maassen. He gave a very clear and interactive insight into Kanban. Starting out with the meaning of the word and an example to support this. Kanban mean ‘visual card’. At the Japanese garden in Tokyo, physical cards were used to support a system of people entering and leaving the garden. When people enter the garden they receive one of these cards and when the leave they had to give it back. When the amount of cards is depleted the maximum number of people present in the garden at that time is reached. This is a way to prevent overcrowding.
A similar system can be used in manufacturing and software development processes. Such a physical card (kanban) is used to contain a relative small work item. A development team is only able to cope with a maximum number of work items at one time, so by limiting the amount of kanbans the team is never able to take on more work until it has finished the previous tasks. This supports and even promotes a continuous flow of work. Because the work items are ‘pulled’ in when an empty kanban appears. It is up to the team to detect these freed up kanbans. Kanbans can also be left empty. This should be a trigger for other team members to ‘do something’ to prevent the throughput of work coming to a hold.
I wrote some more on the subject in my Whitehorses blog.
http://blog.whitehorses.nl/2009/12/17/kanban-in-action-talk-on-devoxx-2009/