Purchasing kanban: see your bottlenecks on a single screen

The invisible problem

Many purchasing emergencies are not caused by missing stock but by missing information. Nobody knows the real status of that critical order until it's too late. "Did you order the material?" "I thought Juan was ordering it..."

Your purchasing board

Three columns are enough to see everything at a glance:

• 1. Request: the need exists but is not yet ordered (e.g. "S275 steel - pending approval").
• 2. Order placed: with the supplier, waiting for delivery.
• 3. Received: in the warehouse, closed.

Watch the middle column. If cards pile up there beyond your work-in-progress limit, you've found your bottleneck: the board makes it visible the same day, not at month end.

How to set it up tomorrow

1. Define the flow. Don't overcomplicate: Request, Ordered, Received.
2. Limit the WIP. The heart of kanban is limiting work in progress. Allow no more than 5 open orders at once in the middle column.
3. Review daily. The board doesn't run itself: 10 minutes every morning to move cards and unblock the stuck ones.

Common mistakes

• Turning it into one more spreadsheet: if nobody looks at it, it's useless.
• Putting everything in: start with critical purchases only.
• Not limiting WIP: if you accumulate infinitely, you don't prioritize.

What to measure once it runs

• Time in each phase: where do orders get stuck?
• Recurring blockers: is it always the same supplier?
• Urgent orders: do they go down over time?