A wrapper fifteen centimeters across, folded over filling, then lowered into oil that is deliberately not very hot so the inside cooks through before the outside darkens. One of them is worth about three ordinary gyoza. It is not a large gyoza so much as a different object that happens to be shaped like one.

It was designed by nutritionists working for the Tsu city board of education, around 1985, as a school lunch item. Three conditions were set: a single item had to deliver the nutrition a child needed, it had to be makeable by hand in the school kitchen that morning, and it had to be something children would be excited to see on the tray.

The third condition is the one that usually gets left off such lists. It is also, plainly, the one that worked. There is a practical bonus too: wrapping one big dumpling per child takes the kitchen staff far less time than wrapping eight small ones.

Something built to satisfy a specification became the thing a generation remembers. In October 2008 local volunteers sold them at the Tsu festival and four hundred went in two days. Restaurants around the city took it up, and the school lunch walked out of the school.