Various goods were exchanged in the southern trade that began with China at the end of the Muromachi period. This product was also introduced at that time. The mouth is doubled so that it can be tied with a lid, and the bottom is made to be stable like a boat sake bottle. And it's heavy and solid like stone. I believe that it was probably brought to Japan as a container for distilled spirits.
The mouth is so well-used that the glaze is thickened, and this is the beauty of miscellaneous ware. It has a solid weight for its size, so you can live with large branches.