Keep an assembly line supplied with kanban cards
A workshop makes wheels, saddles and handlebars for a bicycle assembly plant. First you build to the forecast; then you pull with kanban cards and find out how many cards each part needs so the line never stops and the shelf never overflows.
- Round 1 Build to the forecast
- Round 2 Pull with cards
- Round 3 Tune the number of cards
How it works
The assembly line takes parts from a supermarket, a shelf of bins holding 4 pieces each. A single production cell refills the bins, one at a time, and loses a minute every time it switches parts. When a part runs out, the line lamp turns red and the stopped time counts against you. When parts pile up, average stock goes up. Each round is scored on that balance against the best possible card combination on the same shift.
What you learn in each round
- Round 1: build to the forecastThe cell follows a plan built from the sales forecast. The forecast got the mix wrong, so saddles pile up while the line waits for wheels.
- Round 2: pull with cardsEvery bin carries a card. When it runs empty, you drag the card back to the production board. Only what has a card gets built, and the number of cards caps the stock.
- Round 3: tune the number of cardsCards now return on their own and saddle orders come in waves. Halfway through the shift you change one part at a time and measure the effect.
Replenishment kanban and the Kanban Method
This is replenishment kanban, born in Toyota factories, and the origin of the term: the card is the signal that something was consumed and the authorization to produce again. You size the system from demand during the replenishment lead time, plus a buffer for variation.
The Kanban Method, used by knowledge work teams, applies the same pull idea. Instead of one card per bin, every step on the board has a WIP limit that keeps the team from starting more than the system can finish.
Who it is for and how to use it in class
For anyone who wants to know where Kanban comes from before bringing it to a team, and for teachers of operations, logistics and flow management. In class, have everyone play the three rounds and compare the card setup they chose with their peers. The closing question brings the discussion back to what authorizes starting new work on the team.
What the game simplifies
The cell never breaks down, lost demand does not come back later and the board follows the order in which cards arrive, with no leveling. Each simplification is listed at the end of the game.
Keep practicing
- Practice WIP limits →Watch flow change as work in progress goes up or down.
- Measure what the system delivers →Throughput: the basis of every delivery forecast.
- Run the kitchen at Kanban Pizzaria →Six nights at a pizzeria to feel WIP limits, bottlenecks and classes of service. No sign-up.
- Find the bottleneck in the flow →The stage that sets the pace for everything else.
- Test a change in the lab →Hypothesis, baseline and before and after, without touching the team.
Frequently asked questions
What is a kanban card?
It is a card attached to each bin of parts. When the bin runs empty, the card goes back to production and authorizes one new bin. No card, nothing gets built.
Why does the number of cards cap inventory?
Because each card stands for one bin. With three cards for a part, there are never more than three bins of it between the shelf and production.
How do I know how many cards to use?
Add up consumption during the replenishment lead time, in bins, plus the bin in use and a buffer for demand variation. The game shows that math with the numbers from your own game.
How does this relate to WIP limits?
It is the same pull idea. In replenishment kanban the limit is the number of cards per part; in the Kanban Method it is the maximum number of items in progress at each step.
Do I need an account to play?
No. Your result is saved in your browser. With a free account, the game also counts toward My Progress.
Take pull to a team
The Kanban Game applies WIP limits, bottlenecks and lead time to a product squad, with a leaderboard and seasons.
