1 Ryo 'Genroku Koban' reverse 元 GEN

The Genroku Koban was issued as part of a deliberate debasement ordered by the fifth shogun Tsunayoshi's finance adviser Ogiwara Shigehide, who slashed the gold content of the koban from roughly 85% to 57% in order to address chronic shogunal treasury shortfalls. The mint output was enormous — hundreds of thousands of pieces flooded the market within months — and the resulting inflation was severe enough to become a defining grievance of the Genroku period.

Ogiwara paid for the policy eventually. His successor Arai Hakuseki reversed the debasement in 1714 with the Shotoku recoinage, and Ogiwara was stripped of office and died in disgrace.