Kanban board

Kanban is Japanese for signboard, and the original was literally that: a card on a physical board in a Toyota plant, moved from one column to the next as a part was worked on, so anyone walking past could see how much was in progress without asking. The software version keeps the shape and most of the point. Columns are stages, a card sits in exactly one of them, and the card’s position is its status rather than a field inside it.

That exclusivity is what separates the board from a table grouped by a column, which is the thing it most resembles. In a grouped table an item can be regrouped by any dimension and the grouping is a view. On a board the one dimension is baked into the layout, which is a real cost: a board cannot show you status and owner at the same time, and every team that has tried to solve that by adding a second row of columns has discovered why swimlanes are usually a mistake.

The column header count is not decoration. Making queue length visible is the original purpose of the board, and a work in progress limit (a column that says three and turns amber at four) is the mechanism the method actually cares about. A board with unlabelled columns and no counts is the aesthetic of kanban without the part that changed anything.

Two practical constraints follow from the shape. It needs horizontal room, so on a phone the columns become a swipeable set or a single stage at a time behind a picker, and stacking them defeats the comparison the layout exists for. And dragging cannot be the only way to move a card: a board where status changes require a sustained pointer gesture is unusable by keyboard, so the card needs a menu that names the destination columns as well.