What a kanban board is
A kanban board is a visible surface where work appears as cards that move through columns. Each column is a step in the process. Anyone walking past the board understands in ten seconds what is being done, what is stalled and what comes next.
The board is the visible part of a larger system. The logic of pulling work as needed is explained in the kanban and pull production guide. The focus here is different: how to design the board itself, piece by piece.
It works because it applies visual management: the problem stops hiding in spreadsheets and conversations and takes up a place on the wall.
Columns: the path of the work
Columns mirror the real steps of the process, not the ones that exist on the org chart. Start with the flow the team already uses and give each step a verb as its name.
- Queue or To do: approved work, ready to be pulled.
- In progress: one or more columns, one for each transformation step.
- Waiting: the item has finished one step and awaits the next. This column reveals the hidden queue.
- Done: delivered to the process customer.
Splitting too much creates bureaucracy. Four to six columns cover most cases. If a column never receives a card, delete it.
Swimlanes: separating types of work
Swimlanes are horizontal bands that cut across the columns. Each lane groups a type of work or a priority, and each can have its own rules.
- By product or family: one lane for each part family.
- By class of service: an expedite lane for urgent items, limited to one card at a time.
- By type of demand: planned production on top, maintenance and rework below.
Use few lanes. With more than four, the board no longer fits in a single glance and loses its purpose.
WIP limit: what makes the board a system
WIP is work in process. The WIP limit is the maximum number of cards each column accepts at the same time, written at the top of the column. Without this number, the board is just a message wall.
When a column reaches its limit, nobody pulls new work into it. The team looks downstream and helps finish what is stalled. The limit forces a focus on finishing, not starting.
For a first guess, use the number of people working on the step and adjust later. If the column is always full and the flow jams, the limit is too high. If it is always empty and people are waiting, it is too low. The logic of calculating the size of the loop with physical cards is in kanban sizing.
The most frequent mistake is treating the limit as a suggestion. On the first day of pressure, someone puts "just one more" card in the column, and the limit stops existing. Agree in advance on what the team does when the column fills up: help the next step, investigate the blockage or record the wait. Each answer becomes information for improving the flow.
Cards: what to write on each one
A card represents a unit of work that makes sense to the customer of the step. Cards of very different sizes distort how the board reads.
- A short identification of the item (code or name).
- Quantity or batch size.
- Current owner.
- Date it entered the board, to measure how long it has already waited.
- A visual blocked marker, such as a red magnet, when the item is impeded.
Colors should have a fixed meaning. If each person uses a different color, nobody understands the board.
Avoid cards that mix several items. If a card represents "the week's order", it hides the real progress. Prefer small, comparable units that cross the board in days, not weeks.
Board rules: written agreements
Implicit rules breed arguments. Write them on a sheet next to the board, in a few lines and simple language.
- A new card is pulled only when there is room within the column's WIP limit.
- A blocked card is marked and handled at the daily meeting.
- A card advances only when it meets the step's definition of done.
- The person who did the work is the one who moves the card.
- Urgent work enters only through the expedite lane.
Review the rules when the routine changes. A rule nobody follows should be corrected or removed.
Example: an assembly line board
Imagine a cell that assembles valve sets with three steps and two families. The board below is illustrative and can be copied with adjustments.
| Column | WIP limit | Exit criterion |
|---|---|---|
| Assembly queue | 6 | Component kit complete and checked |
| Assembly | 3 | Torque and fit as per instruction |
| Test | 2 | Passed the leak test |
| Waiting for packing | 4 | Label applied |
| Done | no limit | Delivered to shipping |
Two lanes: family A on top and family B below, with an expedite lane limited to 1. The total internal WIP limit is 3 + 2 = 5 sets between assembly and test, plus the queue. If the test fills up, assembly stops pulling and the operators help with testing. The bottleneck shows up on its own, without a report.
Next step
Draw the board on a sheet of paper before buying any material. List the real steps, set an initial WIP limit per column and write three rules. Test for two weeks at the daily meeting and adjust. To flag problems on the board quickly, combine it with andon. If the goal is an organized team, continue to how to organize your team with a board.
Frequently asked questions
What is a kanban board?
It is a visual surface with columns that represent the process steps and cards that represent the work, with a limit on items in progress per column.
How many columns should a kanban board have?
Between four and six cover most cases. Use the real steps of the process and remove columns that never receive cards.
What is a WIP limit?
It is the maximum number of cards allowed in a column at the same time. It prevents the buildup of started work and forces a focus on finishing.
What are swimlanes for?
They separate types of work, such as product families, urgent items or maintenance, and allow specific rules for each type.
Physical or digital board?
In production, a physical board usually works better because it sits at the place of work and everyone sees it without opening a computer.
Keep studying
Sources
- Lean Enterprise Institute. Kanban (glossário Lean). https://www.lean.org/lexicon-terms/kanban/
- Lean Enterprise Institute. Visual management (glossário Lean). https://www.lean.org/lexicon-terms/visual-management/
- ANDERSON, D. Kanban: Successful Evolutionary Change for Your Technology Business. Blue Hole Press.
- ROTHER, M.; SHOOK, J. Aprendendo a Enxergar. São Paulo: Lean Institute Brasil.
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About the author
Lean Manufacturing & Behavioral Management Specialist
Over 20 years in the automotive and metalworking industries (GM and Dana), Lean Manufacturing practitioner since 2006. SENAI instructor and mentor in Brazil’s Brasil Mais Produtivo program, delivering consulting, training and audits for 50+ companies, combining quality, productivity and people development.
