What is a kanban board?

A kanban board is a picture of your work. You draw a column for each stage the work passes through, and you put each piece of work on its own card. As the work progresses, the card moves one column to the right.

That is the whole idea. Its value is that nobody has to ask for a status update: the board is the status. A manager glancing at it can see which stage is full, which card has not moved for a week, and what is finished.

The simplest board has three columns, and plenty of teams never need a fourth:

• To do: work that is agreed but not started.
• In progress: work someone is doing right now.
• Done: work that is finished.

Kanban is Japanese, and it translates roughly as signboard or signal card. It comes from Toyota's car factories in the late 1940s, where a physical card travelled with a batch of parts. When a station used up its parts, the card went back up the line as a signal to make more.

The point was to stop the factory making things nobody needed yet. Work was pulled forward by demand rather than pushed forward by a schedule.

Software teams borrowed the idea in the 2000s, and from there it spread to every kind of team: marketing, recruitment, maintenance, legal. The cards became digital, but the signal is the same — a card moves when there is capacity to take it, not because a plan says it should.

A board with no cap on the middle column is a to-do list drawn sideways. Everything gets started, nothing gets finished, and the board fills up with cards that are nobody's current priority.

The cap is a number written at the top of a column: at most five cards in progress, say. When the column is full and you want to start something new, you cannot — you have to help finish something first. That feels restrictive for about a week, and then it is the reason work starts moving faster.

There is no correct number. A common starting point is one or two cards per person in that stage, then adjust: if the column is always full and work still flows, raise it; if cards sit there going stale, lower it.

The two get mixed up because both use cards and both came from the same decade of thinking about work. They answer different questions.

Scrum organises work into fixed-length sprints, usually one or two weeks. The team commits to a set of work at the start, and the scope is held still until the sprint ends. It suits teams who can plan a fortnight ahead.

Kanban has no sprints. Work flows continuously, and priorities can change tomorrow as long as the limits are respected. It suits teams whose work arrives unpredictably — a service desk, a maintenance crew, anyone reacting to customers.

Neither is more advanced. If your week is routinely interrupted by whatever came in that morning, sprints will fight you and kanban will not.

• Too many columns. If a stage has never had a card sit in it, it is a step in someone's head, not a stage.
• No cap on work in progress, which turns the board back into a list.
• Cards with no owner. A card owned by the team is a card owned by nobody.
• A board nobody looks at together. The weekly look at what has not moved is most of the benefit.
• Moving a card to Done because it is nearly finished. Done has to mean done, or the board starts lying to you.
• Running the board in a chat group. The message scrolls away and there is no record of who agreed to what.

Sticky notes on a wall work, and for a team that sits in one room they are often the right answer. You see the board whether you meant to or not, which is a real advantage.

A wall stops working when people are not in the room. If your team is out on jobs, or split across sites, the board has to be somewhere everyone can reach from a phone. A digital board also keeps the history — when a card moved, who moved it, how long it sat in each stage — which is what lets you answer whether the work is getting faster.