When people think about Kanban, they usually get the impression that Kanban is either an inventory control mechanism or a system to manage an assembly line of workers. This is due to Kanban’s historical roots as part of Lean Manufacturing and the Toyota Production System.
When I talk about Kanban, especially in reference to using Kanban with software development, I stress the importance of flow; how you pull items through the production system while limiting the work in progress. My favorite thing about Kanban is the Kanban card itself. Kanban gets its name from the card; Kanban translated from the Japanese means “signal card”. According to Lean definitions a Kanban card contains information about a part used in production. It is a signal that tells someone upstream to order more of that part, or move more of that part (from inventory to a production queue for example), or build more of that part. In essence a Kanban card is a visual signal that triggers an action to happen in the workflow.
Kanban has evolved to be used outside of the manufacturing world and has started to gain acceptance in software development. Kanban is also being used in operations outside of manufacturing and software. In his book, Kanban, David Anderson described how Kanban is used to do crowd control at the Imperial Gardens in Tokyo, limiting the inventory or “work in progress” (visitors.)
I had a similar experience this past weekend in Japan. I was on a short weekend vacation in Tokyo with my wife. What had started out as a trip to watch some professional Japanese Baseball, slowly was evolving into a shopping trip for my wife. Hot, tired and trying to avoid shopping for shoes, I suggested we duck into the local Starbucks. As my wife snagged us a table, I tried to order by pointing, smiling, and hand jesters. Somehow I was able to order my old reliable a Tall Soya Chai. After I paid, I was handed my receipt (never walk away in Japan without first taking the receipt) and a strange looking card.
I did not really know what this card was for, but it did say “Soymilk” in English as you can see from the photo. I was intrigued and figured that maybe it was information about the Soya Milk that they use or maybe it was something about the organic certification.
Then I figured that it was probably some rock star Japanese targeted marketing, the Soya Milk company probably paid Starbucks to place an advertisement for their soya milk so you can buy it for use at home. I decided to flip it over since, this being Japan, I figured that there was probably a bar code for my Android phone to scan and I can see the ad. I wanted to see if there was a link to buy it, with a discount, with one click. (I’m sorry, but this is how my mind works.)
To my shock, when I turned it over, I realized that I was holding not a marketing ad, but a real-life Kanban card! The back of the card read in both Japanese and English: “Please hand this card to our Barista at the hand off.” It went on to say at the bottom: “We sincerely serve our soymilk beverages to our customers by using this card to prevent milk allergy incident.”
Wow! As someone with a milk allergy and someone who teaches Kanban, I was blow away. I have been drinking Soymilk Chai for almost 10 years and have been to tons of Starbucks around the world and never have been given anything to signal to the Barista that I received the correct beverage. (Actually I find that the Barista’s in New York consistency screw up my order.)
Now you may be thinking, “Steve, this is a stretch. Kanban is about work in progress and just in time delivery, not coffee.” At the surface you are correct, but Kanban is about using a physical visual signal card (Kanban Card) to trigger an action in a workflow. Usually this trigger is to order more inventory. Sometimes that inventory is car tires (as in the assembly line in Toyota) and sometimes it is people (as in David Anderson’s visit to the park.)
In this case, Starbucks in Japan (I went to several other Starbucks to be sure), uses Kanban to manage the ordering, making, and drink pick-up workflow by verifying (or limiting the work in progress) inventory of Soya beverages made. In the “Soya” case, the cashier starts the workflow by processing the Soya request and gives the Kanban card to the customer and alerts the Baristas to the order. When the customer hands the Kanban card back to the Barista, one Soya beverage is removed from the queue; the number of Kanban cards must equal the number of Soya beverage inventory at the counter. In essence, the Customer “pulled” the work (the Soya beverage) through the system and the Kanban card is ensuring quality.
Remember, a Kanban card is about a visual signal that triggers an action in a workflow. The Soya Milk Kanban card signals to the Barista that they must remove one Soya drink from the inventory of drinks in front of them. (If you have ever been to Starbucks, you know that the Barista may have 5 or even 10 drinks in front of them in “inventory” at any given time.) When you look at this system as a whole, it is pretty simple, yet brilliant. Maybe we can start to use visual signal cards as part of the QA process in software development. I left Japan inspired by Starbuck’s embracement of Lean manufacturing and Kanban for quality!
PS: I tried to bill my employer, Telerik, for the drinks I consumed in Japan this weekend on an expense report, saying it was “market research”. When my expense report was rejected, they told me that the accounting department is now using a Kanban system to maintain quality and my expense report was flagged.
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The opinions expressed herein are my own personal opinions and do not represent
my employer's view in anyway.