I was reading Freddy Balle’s book The Gold Mine: A Novel of Lean Turnaround and I read something that stopped me dead in my tracks. In the book, after months of transitioning a manufacturing plant to continuous flow using Kanban, the Lean sensei asks the innocent question:
Question: What is better than Kanban?
To answer this, one must think of the purpose of a Kanban card. In manufacturing, a Kanban card is a replenishment indicator for a particular part or assembly. In software, we use Kanban to represent a piece of work such as an MMF or user story. Either way, a Kanban card represents WIP (work in process). More Kanban cards means more WIP.
What’s our goal? To increase throughput and reduce latency while minimizing operating expense. Reducing WIP is very helpful. Would be great if we could reduce our WIP as far as possible. How to do that? One-piece flow. So we reduce Kanban cards to zero.
Answer: No Kanban!
If there is no Kanban and you are very Lean, then you have single-piece flow. The holy grail of Lean process. This is what Arlo Belshee and Jim Shore attempted to explained in their LSSC10 session Enough Kanban! Use XP for Single-piece flow. (Please check it out if you haven’t seen it before.) I say attempted because I didn’t get it – I needed to read the above question and answer for the pin to drop.
So what? If you are in an environment where you can do Scrum or XP, then go do so! If not, then Kanban is great place to start. Or finish – in the case of an elite Scrum/XP team that doesn’t need iterations as training wheels.
Kanban in Context
I love Kanban – it is a great tool. One thing that I keep in mind is that Kanban is only a small part of the Lean context in which it lives. Kenji Hiranabe has a great article on InfoQ on this – Kanban Applied to Software Development: from Agile to Lean Please check out Figure 11 TPS Concept Structure: it illustrates that Kanban is just one part of the Lean system of thinking. Of course, it is a great starting place for learning it.
(Aside: I almost had a blog post without images or drawings. Then I decided I needed to do something – anything to make my point more vivid. Please excuse my primitive drawing skills.)