# Friday, 01 April 2011

See also:

·         Part I: How I started to use Scrum

·         Part II: Scrum, but

·         Part III:  Moving away from Scrum

In Part I we looked at how I got into Agile and Scrum. In Part II we explored how Scrum failed to be flexible enough to fit into my unique process. In Part III we took a look at how I got introduced to Kanban, without even knowing it. Today we’ll take a quick look at what Kanban is.

Kanban is a Japanese word that loosely translated means “signal card.”  Kanban’s underlying thesis is that by using signal cards at various points in the production process to indicate the amount of work completed, you can limit the amount of work in progress (WIP) and thus keep the system very “lean” and agile. Work in Progress (WIP) represents inventory and inventory is expensive to keep.

Kanban was originally developed at Toyota as part of the Lean manufacturing movement to facilitate pull systems in a just in time (JIT) production manufacturing process. Work is pulled through the system in single units by demand, instead of pushed in batches. Think Dell computer’s JIT assembly of your laptop as you order it; Dell is pulling a single unit through its production process on demand as opposed to pushing through a batch of computers and selling them pre-configured.

Over the past few years there have been several blogs and books describing a Kanban process as an agile methodology for software development.  There are far more robust explanations of Kanban out there on the Internet, so I will not try to outdo them here, however, let me give a brief overview and then circle back to the system I described in Part III.

As a development methodology, Kanban is an evolutionary process that focuses on the flow of work in progress. Individual items of near equal size are pulled on demand through the system. Kanban focus on the flow of the work, trying to make constant improvements to the flow.  This increases the predictability of the system. Evolutionary by nature, Kanban is designed to facilitate continuous learning and improvement to the process (the Japanese call this kaizen ).  Kanban teams usually put up a “Kanban Board” where they have the process states as columns and sticky notes representing the queue or work items and where they are in the production cycle. This visualizes the production system and allows you to spot areas for improvement.


The Kanban board is the most important item in the system, it represents the production flow. As an item moves from “design” to “development” to “test” and off the board to production, you can get a holistic view of the process and identify bottlenecks. Kanban has a daily standup meeting, not to focus on “what you have done today” since that is obvious via the Kanban board, but rather to focus on the production process and talk about bottlenecks and how to improve them.  For example if you have way too many items queued up in the “tester” queue, you can make changes to the way the work flows through the system (or identify that you need more testers.)

Kanban throws away the concept of a sprint and even estimation  to a lesser degree. Stories are larger in length and scope but you have less of them in your system. If you break down tasks into digestible units of comparable size, by looking at the Kanban board, you know how long it typically takes to get tasks done.  The goal of Kanban is to keep the work in progress as small as possible, at the exact flow rate that the team can handle.  The team will commit to deliver work items at the flow rate, and expedite important work items. As time progresses and the team improves, the flow rates can be adjusted.

Sound familiar? This is the system I stumbled across at my start-up defined in Part III (minus the Kanban board.)  If I had a Kanban board I would have had all of the states (analysis and rules complete, in progress,  etc) on top and had sticky note for each task (the RegEx work) in the workflow and where it was in the process. Since our tasks typically only took half a day and moved from start to finish off the board in about 48 hours and we had a remote team, it would have made sense to have an electronic board. Nonetheless, our quazi-Kanban system limited work in progress, allowed the developers to pull work out of the queue in a very predictable pattern, and produced quality results. The most important part is that the system was flexible.

Since we started as a Scrum process and evolved to a more lean manufacturing influenced production system, I learned that no single development process (such as Scrum) is a “silver bullet”.  I also realized that all of the “features” of Agile are available to you and you can mix and match them-as long as you adhere to the Agile values put forth in the Agile manifesto.  More on this later in the last part of this series.

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