Before the shoreline of Tokyo Bay was reclaimed, short-neck clams (asari) and hard clams (hamaguri) used to be abundant around the mouth of the river Fukagawa. During the Edo Period, local fishermen came up with the recipe for this dish: the clams are deep-fried, then blended with scallions and seasoned with miso, and this mix was served over hot rice. Because these shellfish were readily available and easily affordable, this was an important source of nutrition for the townspeople.