Kōshū ichibukin (one-bu gold of Kai)
Later 16th century–1860s ・ gold ・ 16th century ・ Kai, the Kōshū gold mint
A provincial gold coin struck from gold out of the mines of Kai, marked to the base-four scale of one ryō = four bu = sixteen shu. As a gold coin counted by the piece rather than weighed, it is an early case. Tradition says it was put in order in the time of the Takeda, but most surviving pieces are of Edo manufacture, and this one is a kōjūkin, carrying the punch 'jū' on the back. The units passed straight on into the koban of Edo.