This pottery with raised slip decoration discovered at the coast of Gosan-ri, Jeju, features narrow, flat bottom and gradually widening body as it moves up to the mouth. It is the first of its kind discovered in Jeju-do, but similar potteries have been excavated in Gangwon-do and the Southern coastal areas although those from Gosan-ri have significantly larger mouth. This pottery is quite splendid decorated with parallel lines and geometric designs via the technique of applying raised slip. It shows, however, the beauty of moderation though the thick triple lines.