Loach are laid in a shallow iron pan with their broth and set over a burner. Onto them goes a mound of burdock, shaved into slivers, and spring onion piled far higher than looks reasonable. Then you wait. As the onion wilts and sinks into the pan you add more from the bowl beside you, and you keep adding until the pot is finished.

The dish is traced to a man who opened an eating house at Komagata in Asakusa in 1801 and began serving loach in a pot and loach in soup. Edo avoided the meat of four-legged animals, so freshwater fish carried the job of feeding people who needed strength. Loach were cheap, came out of the rivers nearby, and were held to be restorative. A guide to the notable eating places of the city, published in 1848, already lists the shop by name.

The sign is written dozeu rather than the ordinary spelling, and there is a reason. When the shop burned in the great fire of 1806, the four-character spelling was judged unlucky, and a signwriter was asked to render it in three.

A shop that dropped a single character from its sign for luck has been open for two hundred years, which does not prove anything, and is difficult to argue with.