It starts with the postwar food stalls, the ones standing at the port in Komatsushima, and it moved from there into the city of Tokushima and multiplied.

Who it was made for explains what it actually is. Laborers and market workers wanted something fast, filling, and strongly flavored at the end of a shift. This area had a substantial soy sauce brewing industry of its own, so building a soup around dark koikuchi soy sauce was the obvious move to make.

Pork bone stock, that dark soy tare, and sugar and mirin worked in for sweetness. On top of that goes pork belly, simmered until it is sweet and salty and falling apart at the touch. Then a raw egg is cracked over the top of it, and you break the yolk into the soup yourself with your chopsticks.

The yolk rounds everything off, and what you end up eating tastes a great deal closer to sukiyaki than it does to most bowls of ramen. Which is precisely why ordering a bowl of rice alongside it is standard practice here rather than an optional extra. This is not really a bowl of noodles that happens to have rice available on the side. It is a dish engineered from the beginning to be eaten together with rice, and the noodles are simply one component of it.