1 Bu 'Bunsei Ichibukin'

The Bunsei Ichibukin was struck beginning in 1819 as part of a broader debasement policy during the Bunsei era reforms under the Shogunate's financial administration. The gold content had already been declining across successive ichibukin issues since the early Edo period — the Genbun recoinage of 1736 being the most dramatic single reduction — and the Bunsei issue continued that trajectory, though more modestly than some predecessors.

Circulation was deliberately managed through periodic recall-and-reissue cycles, which the Shogunate used to generate seigniorage revenue. Surviving examples outside Japan are almost entirely from treaty-port export in the 1850s and 1860s, when foreign merchants arbitraged Japanese gold-silver ratios against world markets.