Tokkuri (Sake Flask) Generic term for ceramic flasks used to serve sake. Tokkuri come in all shapes and sizes. Usually holds about 360 ml. of sake. The most popular styles are Bizen, Iga, Shigaraki, Imari, and Mino. Choshi is another term for tokkuri, but most often choshi are made of metal and have a handle. After using your flask, wash it out with water and let it dry in a well-lit and airy space.