This is a plate made of "Karatsu-yaki," a type of pottery primarily produced in Karatsu City, Saga Prefecture. Karatsu-yaki is characterized by its rustic texture, made from roughly textured clay, and a variety of decorative techniques. It is also known for its appealing aging process, becoming more lustrous and acquiring a deeper character with use. The history of Karatsu-yaki is long; it was a center for pottery until the discovery of porcelain stone in Arita in the early 17th century, which led to the birth of Japan's first porcelain. It has a history of being cherished by many tea masters as a masterpiece of the tea ceremony and is also known as a vessel of "beauty in utility." I received it as a gift, so I looked it up on Google.