This is Imari ware, with a red "Kaku-Fuku" (角福) mark on the back. It's likely from the late Edo period to the early Meiji period. It's not Ko-Imari (old Imari). It's an antique. Dimensions are: diameter 12.2cm, foot diameter 7.6cm, thickness 2.4cm. Thank you. The design is very beautiful. It appears to be unused. These are my measurements, so there may be some error. No box included.