Kochi

Kochi Prefecture on Shikoku is the home of Goishicha (碁石茶, "go-stone tea") — a rare double-fermented dark tea produced in the mountainous city of Otoyo. Goishicha appeared around the 18th century, peaked in the late 19th–early 20th century, and nearly collapsed during the Showa era; in 2018 it was officially recognised as an Intangible Cultural Property of Japan under "production methods for fermented tea in the mountainous region of Shikoku" — one of only two recognised Japanese post-fermented teas alongside Ehime's Ishizuchi-kurocha.