What is Kanban?

History

Kanban was originally invented by Taiichi Ohno at Toyota in the 1950ies to improve manufacturing efficiency in their automotive factory.
It has since been adopted by many industries - from manufacturing to software development to knowledge industries - due to its intuitive simplicity while being effective in improving outcomes.

The core idea of Kanban

The core idea of Kanban is to write down every task on a card and put that coard on a so-called Kanban board.

The prototypical Kanban board is divided in three columns:
Requested or Backlog - for known work that has not yet been started
Doing or In Progress - for work actively being worked on by someone
Done - for completed work.

The Kanban board can be (and originally was) a literal board with paper cards stuck to it.

The operation of a Kanban board is very simple: whoever starts a work takes a card from the Requested column, writes their name on it and moves it to the Doing column.
Once the work is completed the card is moved to the Done column and the next card can be taken from the Requested column.

Kanban practices

Visibly, practising Kanban is putting up a Kanban board with cards, but to ensure success we want to follow a number of well-known Kanban practices.

The important Kanban practices are:
1. Start where you are
2. Visualize work
3. Limit work-in-progess (WIP)
4. Manage flow
5. Make policies explicit
6. Collaborate and improve

The following sections briefly describe these practices:

Start where you are

When we start out with Kanban we want to limit the amount of change that we introduce. Specifically, we do not want to change the work processes themselves, at least not initially. The emphasis is to use existing tools and processes as much as possible and make only gradual changes (the first change being the setup of a Kanban board). In fact, it's possible (and not uncommon) to start practising Kanban with a physical board and a collection of paper cards.

Visualize work

To visualize work is to make all work visible as a Kanban card so it's state of completion is known and it can be appreciated and planned for. It also helps to uncover unplanned work and limit the work in progress.

Limit Work-In-Progress

While some of us may be proud of being able to multi-task, the reality is that there is a cost to switch between tasks. Switching from one task to another not only postpones the completion of the first task, but it also requires a change of (mental or physical) context, a change of tools. For humans it comes with a cognitive burden that can significantly impact effectiveness and emotional state. Limiting the work in progess then means to delibrately avoid such switching by not taking on new work before previous work has been completed. It puts the focus on finishing work rather than starting new work.

Manage flow

Ultimately we deliver value when we complete work - by definition incomplete work is of lesser - if any - value. The goal then should be to complete as much work as possible. By following the Kanban practices we strive to improve the flow of work to completion, i.e. to ensure that no work falls by the wayside and that work is completed in a timely manner.

Make policies explicit

Sometimes we have unspoken or unwritten rules about how the work is to be done or what is necessary for the next step. In Kanban we strive to make such policies explicit by writing them down and making them accessible to the team. This improves shared understanding of the work process and reduces rework.

Collaborate and improve

Ideally a Kanban board helps a team to come to a shared understanding of the work that needs to be done. It should help to identify work or team members that are stuck on a particular item so others can help before the situation escalates. Ideally the team should from time to time review their work and how it's being done and agree on relatively small, gradual changes (also known as continuous improvement). By making small changes that are worked out collaboratively and agreed on by everyone, we limit the risk and avoid the cost of a big transformational change. Following the "make policies explicit" practise we shall write down any such changes in our new policies.