Kanban is often a vaguely understood term. Two professionals talking about kanban usually have different level of understanding, despite both deriving good practical value from their knowledge.
So, what exactly is Kanban – a card, a board, a system or a method?
The short answer is – all of them.
The word ‘kanban’ has its origin in both hiragana (Japanese language) and Kanji (Chinese language). In hiragana, it means a ‘signal card’ while is kanji it means a ‘sign’ or ‘large visual board’.
Beyond the etymology, ‘kanban’ as a concept was popularized by Taiichi Ohno (former Toyota vice president) who took inspiration from how supermarkets stock their shelves and promoted the idea of Just-in-Time manufacturing in Toyota – using kanban cards as a signal between two dependent processes to facilitate smoother – and just in time – flow of parts between them. With time, the idea of kanban evolved to be more than just a signal card. First in the manufacturing world, and now in IT industry, a ‘Kanban System’ is characterized by three key features:
- Visualization of work items – using signal cards, or some other means.
- A pull-based system, where work is pulled by the next process, based on available capacity, rather than pushed by the previous process.
- Enforcing WIP Limits – limiting total work in progress narrows the team focus, in turn streamlining the flow of work and improving product quality.
A team that uses Kanban System to track and manage the flow of work may often use a board to visualize the items that are in progress. Such a board is called ‘Kanban Board’. Those practicing Scrum may think of Scrum board as a very basic version of Kanban Board.
Now, what about the Kanban method?
‘Kanban Method’ is a term coined and popularized by David J Anderson who, over the past ten years, has evolved the kanban concept into a management method to improve service delivery and evolve the business to be ‘fit for purpose’. It is not project management method or a process framework that tells how to develop software, but is a set of principles and practices that help you pursue incremental, evolutionary change in your organization. In other words, it will not replace your existing process, but evolve it to be a better ‘fit for purpose’ – be it Scrum or waterfall.
While the idea of kanban has evolved from a signal card to a management method, its emphasis on visualization and pull-based work management have remained intact.
The six key practices outlined in the Kanban Method include:
- Visualize your work
- Limit work-in-progress
- Measure and Manage flow
- Make policies explicit
- Implement feedback loops
- Improve collaboratively, evolve experimentally
Besides these six practices, other key concepts in Kanban Method include - Work item types, Classes of service, Swim lanes, Expedite Lane, Ready queue or Input buffer, Replenishment meeting and Daily Kanban (runs different than Daily Scrum). The key metrics that Kanban teams use to improve the flow of work (and service delivery) include Throughput, Cycle/Lead time distribution, Control chart and Cumulative flow diagram.
To summarize, we can say… Kanban Method is the most powerful and most evolved concept among different kanban terms - it uses Kanban board (among several other things) and helps teams implement a pull-based work management system while pursuing an evolutionary change that enhances their agility.