What is the Japanese technique "robatayaki" used for?

Robata originates from a centuries-old country style of cooking by northern Japanese fishermen around a communal hearth (irori) that serves as a cooking area and a source of heat, found on the northernmost island of Japan, Hokkaido. The fishermen needed a way to cook on the boats, so they encased binchotan coals in a stone box to protect the boat from the intense heat.