It is made in a single pan. A white broth of pork and chicken bone goes in with cabbage, bean sprouts, pork, fish cake and whatever came off the boats that morning, everything is cooked together, and then the noodles go into the same pan and boil there. They are not cooked separately and transferred. That is the difference between this and almost every other noodle dish of Chinese descent in the country.

It is credited to the first proprietor of a restaurant in Nagasaki in the middle of the Meiji period. There were a great many students from Qing China in the city then, and he wanted to put something cheap and substantial in front of them.

The noodles are made with tokaku, an alkaline solution particular to Nagasaki, and that requirement is written down in the trade's own code of practice. Which means the name does not travel easily, however far the dish itself has gone.

Nobody agrees on where the word came from. One account traces it to a greeting in the Fujian dialect. Another points at a Chinese verb meaning to mix things together. Every explanation on offer has the same shape: the name arrived here from somewhere else, along with the person who made the first bowl.