Kuroishi yakisoba uses a thick flat noodle, heavily coated in a sweet-salty brown sauce. That much is ordinary enough. It is a substantial thing already. Then somebody poured soup over it.

The account given locally is that this happened in the late 1950s or the early 1960s, at a shop standing near a middle school. Children came in on the way home from class, the yakisoba sitting on the griddle had gone cold by then, and hot soba broth was poured over the top of it to warm the thing up before it was handed over the counter.

So the thing arrives at your table in a donburi rather than on a flat plate. Sauce-coated noodles floating in a clear broth, with tenkasu and scallion scattered on top, which is a combination that sounds wrong in every single particular and somehow is not.

In recent years shops across the city have taken it up, and Kuroishi describes it, quite accurately, as an unusual thing to find anywhere else in the country. What began as a single practical gesture, a way of dealing with food that had gone cold in front of a hungry child after school, has ended up as the name of a dish. The improvisation itself turned out to be the recipe, and nobody has seen a reason to improve on it.