This is the "Tenryu Gama" kiln, a Hagi-yaki pottery workshop in Hagi City, Yamaguchi Prefecture. These are ceramics created with the concept of simple designs yet warm, earthy vessels. I received these a while ago, but the box and product information are no longer available. They have been stored in a warehouse for a long time. The diameter is approximately 13.5cm, the height is approximately 3.0cm, and it is a set of 5.