This appears to be Tamba ware. It's a plate made by an artist. Diameter is approximately 15 cm. It's being sold as a set of two, but one is also available upon request. It has a rim, so it's suitable for dishes with a little bit of liquid, and it's also useful as a side plate. The price was set at 3500 yen per plate. The listed price is for one plate. For two plates, the price is 4500 yen.