An adorable, charming ochoko sold to me at the Tokyo antique market as Bizen-yaki (bizen ware) from wood-fired kilns in Okayama prefecture, made with the dense Bizen clay that brings local Omachi rice to life. Handmade, but without the artist's signature or kiln stamp...so one cannot be certain.
The lip is cast with an earthy green glaze from the natural ash of the kiln. It's an excellent size, with a relatively thin lip, reducing the distance between sake and tongue--making the sake taste sweet.
I strongly recommend pairing this ochoko with a tokkuri of similar make, such as a bizen tokkuri.
Measures 4cm tall by 4.5cm diameter.