Around 1950, people in Sasebo went and asked the US navy base directly how the burgers were made, and then started making them themselves. Sasebo is described locally as one of the places where the hamburger first entered Japan, and the early shops stood near the base, selling to Americans rather than to anyone else.

The definition, when it was eventually written down, turned out to be about the process rather than about any recipe. Cooking must not begin until the order is placed. The business must be headquartered in Sasebo. Fresh raw vegetables must be used. An original sauce must be part of it.

In January of 2007 a certification system was set up, assessing shops on originality, on reliability, on use of local produce, and on handmade preparation. More than twenty-five burger shops are operating in the city at present.

What that means in practice is waiting. You place your order, and then you stand there for several minutes while somebody builds the thing from the beginning, and there is simply no way to shorten this, because the waiting itself is written into the definition. A city took the fastest of all possible foods and then formally required it, in writing, to be slow.