Milk Kanban

When people say Kanban, they tend to think of a specific set of practices. Whiteboards & sticky notes (both almost universally virtual). Tasks moving through columns that represent workflow. Every now and then, WIP limits even.

As often as we do it with other things, it reduces a broader principle to a set of oversimplified techniques, which, in turn, tend to underdeliver in many contexts.

Kanban

In its original meaning, Kanban represented a visual signal. The thing that communicated, well, something. It might have been a need, option, availability, capacity, request, etc.

In our Kanban systems, the actual Kanban is a sticky note.

It represents work, and given its closest environment (board, columns, other stickies, visual decorators), it communicates what needs, or needs not, to be done.

If it’s yellow, it’s a regular feature. If there’s a blocker on it, it requests focus. If there’s a long queue of neighbors, it suggests flow inefficiency. If it’s a column named “ready for…” it communicates available work and/or handoff.

A visual signal all the way.

Visual Signals

Let’s decouple ourselves from the most standard Kanban board design. Let’s forget columns, sticky notes, and all that jazz.

Enters Kasia, our office manager at Lunar. One of the many things Kasia takes care of is making sure we don’t run out of kitchen supplies. The tricky part is that when you don’t drink milk yourself, it becomes a pain to check the cupboard with milk reserves every now and then to ensure we’re stocked.

Then, one day, I found this.

A simple index card taped to the last milk carton in a row stating, “Bring me to Kasia.” That’s it.

In the context, it really says that:

  • we’re running out of (specific kind of) milk
  • we want to restock soon
  • there’s enough time to make an order (we don’t drink that much of cappuccinos and macchiatos)

But it’s just a visual signal. Kanban at its very core.

Simplicity is the King

What Kasia designed is a perfect Kanban system. It relies on visual signals, which are put in the context. Even better, unlike most Kanban boards I see across teams, the system is self-explanatory. Everything one needs to know is written on the index card.

That’s, by the way, another characteristic of a good Kanban system. It should be as simple as possible (but not simpler). Our workflow representations tend to get more and more complex over time by themselves; we don’t need to make them so from the outset.

It’s a safe assumption that, almost always, there’s a simpler visualization that would work just as well. We, process designers, often fall into the trap of overengineering our tools.

And it’s a healthy wake-up call when someone who knows close to nothing about our fancy stuff designs a system that we would unlikely think of. One that is a perfect implementation of the original spirit, even if it doesn’t follow any of the common techniques.

Because it’s all about principles, not practices.

That’s what we can learn from Milk Kanban.

Comments

12 responses to “Milk Kanban”

  1. Johanna Rothman Avatar

    I love this! The very simplicity makes it easy to use, which is the point of a signal.

  2. theo Avatar
    theo

    Ah yes lets use a Japanese word, because we are creatively bankrupt and replace another perfectly fine word(signboard) ro pretend we did something new and cool. A post it note is not a kanban. Pure idiocy.

  3. Daniel Avatar
    Daniel

    > The tricky part is that when you don’t drink milk yourself, it becomes a pain to check the cupboard with milk reserves every now and then to ensure we’re stocked.

    If checking the milk reserves once a day is too much of a pain for a person hired as an office manager, the person should self-respect on their choice to take the on that role.

  4. Jamine Avatar
    Jamine

    > A post it note is not a kanban

    Theo, you might have to reconsider your idea of “idiocy”, potentially in front of a mirror. “Kanban” is not a noun so of course a post-it can’t be one. The concept originated from Japan (Toyota factories to be specific) so it makes absolute sense to use the original word. Their method did not use a signboard at all, Kanban *is the system*, which you would learn with a couple minutes of focused googling.

  5. Derek Jarvis Avatar

    Just posting to say thanks for the brief and insightful article. Hoping this helps balance some of the unnecessary negativity here.

    We should always be willing to sit back and admire simple solutions.

  6. CR Drost Avatar
    CR Drost

    Nit: this is not Milk Kanban, it is, in fact, Kanban. The things that you are used to in Scrum are more of a “Monopoly Money Kanban,” etc.

    To be clear, a major problem affecting Japanese manufacturing, was factories full of WIP because I just made a subassembly, I have nothing else to do, the parts are right here, I might as well make another of the same subassembly to get ahead of the work. Taiichi Ohno visited the US and saw how a supermarket works and thought, “that’s what I want my factories to be, there are 10 lemons, if you grab five to make lemonade and you grab a sugar bag from over there, someone notices that the lemon pile is too low and grabs more from storage, someone else restocks the sugar bags.” (This is a bit of an oversimplification, if memory serves me right he was using the supermarket metaphor before he went to Toyota and before he visited the US.)

    To do this in a manufacturing plant, he had everything in the middle put into a plastic tub or on a rolling skid or so, and on the side of the tub was a reorder form, if you use the part in the tub you have to send the card back to reorder another of those parts to be made. Then management can make sure that there is exactly the amount of Subassembly B1a6 by controlling the cards that are there, and if that doesn’t work you figure out what the upstream team needs.

    And those little durable reorder forms were on card stock for durability and were called… kanban.

    Then people wanted to run software companies like manufacturing plants, completely disregarding that in manufacturing you are trying to make a lot of “The New ST57g”, fill in your own product, but in software (and other industries like mechanical subcontractors—welders, electricians building buildings to an architectural plan, say) you only make any given product once or twice and then service/maintain it extensively. So they looked to lean manufacturing principles, and Toyota had this kanban system, and so “they do all their work from little cards, we need little cards too!”. Not a moment was spared to say “oh, part of why this works so well is that the same card is being constantly reused, you don’t have to groom the cards constantly, it controls a specific source of waste in the system.”

    This is not to say that the entire enterprise is bankrupt when applied to software: see Dominica DeGrandis’ “Making Work Visible” for a clever rebuttal to my naysaying, where if you can get employees to make tickets for all of their maintenance tasks and HR presentations they have to watch and anything else that they have to do, suddenly a neo-kanban system is answering questions about where the time has gone. But it fundamentally misunderstands the biggest possible source of gains, which is that the whole team should be working together (or at least working in pairs and trios) where scrum usually puts everyone on a separate task.

  7. Connor Avatar
    Connor

    I think that previous commenters are ignoring the fact that the Kanban system as used in software steals from a previous Kanban stocking system used in manufacturing, and that this example is actually textbook Kanban.

    From the Wikipedia for Kanban:

    “Kanban aligns inventory levels with actual consumption. A signal tells a supplier to produce and deliver a new shipment when a material is consumed. This signal is tracked through the replenishment cycle, bringing visibility to the supplier, consumer, and buyer.”

    I think that this implements that philosophy perfectly. We’re not buying milk before we need it and have a place to store it, but we also avoiding someone needing milk and not having it.

    And for reference, my understanding is that “kanban” is literally the Japanese word for signboard, and that the name is then extended to the system, unsure if the above comment misunderstood that, or if they just take issue for using Japanese phrases in place of English ones?

    I know that my own personal todo lists benefit from Kanban process (though I wish I had better in-progress limits) and I agree that at work our processes can build up layers of additional process that sound good, but end up just being a lot of paper pushing. I’ve recently been on a process-trimming fight where I’m trying to ask “do we really need to do this, does the benefit of X outweigh the time cost?”

  8. Cody Avatar
    Cody

    > Ah yes lets use a Japanese word, because we are creatively bankrupt and replace another perfectly fine word(signboard) ro pretend we did something new and cool. A post it note is not a kanban. Pure idiocy.

    Well, Theo, we use a Japanese name because that’s where it came from. Have you ever heard of a tsunami, or kamikaze, or sushi? These are also Japanese words we use in the English which have more nuanced meanings than just googling their “literal translation”.

    Additionally, I can understand that being as unintelligent as you are must be difficult but if you try your hardest you might be able to google “kanban” and “signboard” to learn that one refers to a methodology and the other does not.

  9. Pawel Brodzinski Avatar

    @CR Drost
    I’m totally with you on the observation that the nature of work is different between manufacturing (repetitive items) and knowledge work (unique tasks), and thus, the nature of visual signals we use should (most probably) differ, too.

    What started as a Toyota-specific process (TPS) was later generalized to Lean Manufacturing and adopted by other automotive companies. Then, other industries. At some point, it was further generalized to just Lean, and in the early 2000s, there were first approaches to adopt it in IT (Poppendiecks).

    So it’s not like we have one rigid solution where kanban is a card in a pile of manufacturing pieces, but a continuously evolving body of knowledge that is being used in increasingly different contexts.

    What’s more, Kanban was adopted as the name for a method popularized in IT.

    Coming back to the original point, if we look at principles and not specific practices, we will be talking about visualizing work. On a factory floor, an important visual signal was a workstation running out of needed parts. In a software development team, we similarly want to have enough work items for every “station.” That’s why smart teams pay attention to queues on their boards. They provide the same signal as piles of parts on the factory floor. And we could have similar pull signals when “ready for…” columns get emptied.

    So, it’s not as important what exactly a visual signal looks like. One of the famous Kanban systems is in the Imperial Palace Garden in Tokyo, where returnable physical tokens are used as free admission tickets so that the park doesn’t get overcrowded.

    Does the system look the same as on a Toyota factory floor? No. Can we call it a Kanban system? Absolutely. It visualizes important aspects of workflow and limits work in progress.

  10. Pawel Brodzinski Avatar

    @Connor,
    You’re right on the fact that, by now, the word bears so many different meanings. People tend to apply the context closest to their own and don’t look for other perspectives.

    We can apply the same principles in manufacturing, software development, and managing personal to-do lists.

    My beef with what my industry (IT) does is that we standardized specific techniques to the point they are petrified. Few people try to understand the whys behind or get where the ideas came from initially.

    Oh, but we’re so quick to quarrel over what the word means. Oh, well…

    BTW: applying Kanban to managing personal task lists is one of my favorite tricks. And I pay homage to Jim Benson & Tonianne DeMaria’s Personal Kanban here.

  11. Noncey Avatar

    I just wanted to chime in and say thank you to everyone who bodied Theo’s ignorant, arrogant, and useless comment. Thanks for the article!

  12. Pawel Brodzinski Avatar

    By the way, after the comment threads here and on HackerNews (https://news.ycombinator.com/item?id=43373157), I wrote a follow up post, where I try to look at some of the critique from a systemic perspective: https://brodzinski.com/2025/03/respect-make-or-break-culture.html

Leave a Reply

Your email address will not be published. Required fields are marked *