Thick white bread, toasted, spread with butter, and then sweet red bean paste piled on top of that. The salt in the butter and the sugar in the beans meet on a hot surface, which is more or less the entire idea.

It is traced to a coffee house in the Sakae district of Nagoya at the end of the Taisho period. Students there had taken to dunking their buttered toast into bowls of sweet bean soup, and the woman who ran the place watched them do it and concluded that the beans might as well go on the bread to begin with.

The city has a second habit worth explaining alongside it. Order a drink in a coffee house here in the morning and food arrives with it, unrequested and unbilled — toast, a boiled egg, sometimes more. This is called morning service, and it is generally said to have started not in Nagoya but in Ichinomiya.

In the late 1950s Ichinomiya was rich on textiles, and the weaving sheds were too loud to talk business in, so the mill owners did their dealing in coffee houses instead, several times a day. One proprietor started giving those customers a boiled egg and some peanuts with the morning coffee. Between the beans and the egg, this is a region where things you did not order keep arriving on the table.