Camellia oil is worked into the surface as the dough is drawn out, because the islands are covered in camellia. The oil is why a strand two millimetres across does not break — this is closer to somen than to what most people picture when they hear udon.

The broth is made from ago, the flying fish taken in the water around here. They are grilled before they go into the pot, and the char stays in the finished stock.

The way it is eaten is the unusual part. The pot is kept at a rolling boil on the table and you lift noodles straight out of it into your dipping bowl, a few at a time, for as long as it lasts. The boiling pot is said to resemble the cauldron of hell, which is where the name of the method comes from. Nothing is ever transferred to a serving dish.

One account has the technique arriving with the embassies sent to Tang China between the seventh and ninth centuries, and the resemblance to Chinese methods is offered as the evidence. Its name gets listed alongside Sanuki and Inaniwa when people count the country's udon. Outside the islands, though, it is still not particularly well known, which is a strange position for something to occupy.