 "Wappani" ( is a miso-soup-based dish unique to Awashima island off the coast of Niigata, Japan.A cedar flask (""wappa"") is filled with miso soup, fish and vegetables and it is heated by dropping in hot rocks, which quickly bring it to a simmer.Hot rocks retain their heat for hours after being taken from the fire, so a hot meal can be prepared without the use of fire.