A Kogaratsu flat cup fired in the Kotouge kiln of Mt. Uchida in the 1620s. A flower pattern inlaid with white cray appears on the glossy jet-black skin. The Kotoge kiln, which was run by Korean potter Soden initially from Gimhae, Gyeongsangnam-do, is one of the few kilns that crafted Mishima during the Kogaratsu era. Although the glazing tone is different, the style of this piece is the same as that of Buncheong.

It has an appropriate depth and can be likened to a flat sake cup. The side sticking part makes it easy to hold, and the distortion of the vessel is also suitable for drinking sake. Although it is an excavated item, there are no other noticeable defects.