The Kan'ei Tsūhō series had been in continuous production since 1636, but the variant carrying the reverse character 元 (Gen) was introduced in 1741 as part of an effort to track output across the expanding network of authorized mints. By the mid-eighteenth century, production was distributed across multiple locations — including Edo, Osaka, Sendai, and domain-operated facilities — and reverse characters served as a practical administrative device rather than a mark of prestige. The Gen reverse is associated with the Sakamoto mint in Ōmi Province.
The Kan'ei Tsūhō series had been in continuous production since 1636, but the variant carrying the reverse character 元 (Gen) was introduced in 1741 as part of an effort to track output across the expanding network of authorized mints. By the mid-eighteenth century, production was distributed across multiple locations — including Edo, Osaka, Sendai, and domain-operated facilities — and reverse characters served as a practical administrative device rather than a mark of prestige. The Gen reverse is associated with the Sakamoto mint in Ōmi Province.