I believe this is likely a sencha tea bowl. It's an old piece of Yashima-yaki ware. It has desirable crackle and staining from frequent use. There is a small chip on the rim in the image, as well as a crack (nyu). Diameter: Approximately 6.2 x 6.2 cm Height: Approximately 4 cm Sizes are approximate. The color may differ slightly between the actual item and the image. As it is an old item, there are age-related scratches, stains, and other imperfections.