This is a traditional awamori flask, called a Dachibin: originally designed to be carried and worn against the hip, hence the curved shape and shoulder strap. The cordage for the strap is handmade and original-- definitely getting up there in years and not for active use. However, the flask itself definitely is suitable for active (if careful!) use, either for awamori, shochu, or even sake. Age is approximate and estimated to be mid to early 20th century.
This flask comes from the Tsuboya-yaki ceramic tradition and is hand painted and marked by the artist. It makes for beautiful decoration but also imbues a very special mood to awamori and sake service.