The word "Kanban" is used in three separate ways, and the fact that they are rarely distinguished clearly is the source of a lot of confusion in Agile circles. Here is what each one actually means.

Kanban — the Japanese word

The word itself is Japanese. It is a noun that translates loosely as "signal card" or "signpost" — a physical sign that conveys information. The word existed in Japanese long before Toyota adopted it, and in Japan you will still see it used to refer to shop signs, menu boards, and advertising hoardings. Nothing to do with Agile.

Kanban Systems — the Toyota innovation

The second meaning comes from Taiichi Ohno, an industrial engineer at Toyota in the 1950s. After visiting the United States and studying how supermarkets managed inventory — ordering just enough stock to replace what customers had actually bought — Ohno applied the same logic to manufacturing.

Toyota was competing with General Motors and Ford, both of which had the financial muscle to hold large stocks of parts in warehouses. Toyota could not afford that. They needed a system for receiving parts just in time — exactly when a production station needed them, not before.

The solution was elegantly simple. A physical card — a Kanban — was placed inside each box of parts. When a box was nearly empty, the card was sent upstream to the supplier as a replenishment signal. A new box arrived just as the old one ran out.

The important thing to understand is that in a Kanban System, the Kanban is the upstream signal, not the item flowing downstream. It is a pull signal — an indication that the system is ready for more. This distinction matters because it explains why Kanban Systems protect against overburden: if all the pull signals are in circulation, no new work can enter the system. The Tokyo Imperial Palace Gardens use exactly this logic during cherry blossom season: a limited number of entry cards means the garden is never overcrowded. Each returned card is a pull signal allowing one new visitor in.

The Kanban Method — for managing knowledge work

The third meaning is the one most people in Agile organisations are actually referring to: the Kanban Method, developed by David J. Anderson in the mid-2000s, which applies Kanban System thinking to knowledge work.

This is where it gets commonly misunderstood. Many people believe that the Kanban Method simply means putting sticky notes in columns labelled "To Do", "Doing", and "Done". That is a visual board. It is not, by itself, a Kanban System.

For the Kanban Method to actually function as a Kanban System, it requires Work-in-Progress (WIP) limits — a cap on how many items can be active in each stage at any given time. Without WIP limits, there is no pull signal in circulation. Work simply piles up wherever it arrives. The board becomes a tracking tool rather than a flow management system.

WIP limits create the vacant slots that function as pull signals. When an item moves from one column to the next, it opens a space. That space is the Kanban — the upstream signal that the previous stage can now pull in new work. The limit is what makes the system work.

Why it matters

Understanding the distinction between these three definitions is not pedantry. It shapes how you implement and use each one. A team that installs a visual board without WIP limits has a useful communication tool. A team that understands what a Kanban System actually is — and designs their board accordingly — has a mechanism for managing flow, reducing overburden, and making their work sustainable.

One word. Three meanings. All correct. Now you know which is which.