Kōshū Isshukin — "Kai Province one-shu gold" — were emergency issues produced in Kai, the former domain of the Takeda clan, using locally sourced gold from the famously rich Kurokawa and Yuzuruha mines. The Tokugawa shogunate had not yet fully consolidated its national coinage system in the mid-seventeenth century, and provincial gold pieces like this one filled the gap.
These were eventually absorbed and demonetized as the Edo monetary framework tightened, making surviving examples products of a window that closed quickly.
Kōshū Isshukin — "Kai Province one-shu gold" — were emergency issues produced in Kai, the former domain of the Takeda clan, using locally sourced gold from the famously rich Kurokawa and Yuzuruha mines. The Tokugawa shogunate had not yet fully consolidated its national coinage system in the mid-seventeenth century, and provincial gold pieces like this one filled the gap.
These were eventually absorbed and demonetized as the Edo monetary framework tightened, making surviving examples products of a window that closed quickly.