Genroku koban
AD 1695–1710 ・ gold ・ 17th century ・ Edo gold mint
obverse
reverse
The koban that came out of the recoinage led by Ogiwara Shigehide, inspector of accounts, in the eighth year of Genroku. The weight was no different from the Keichō, yet the fineness of the gold fell from the 87 per cent range to 57 per cent. With that much more silver in it, it is whiter, thicker, more brittle. The single character 'gen' punched at the upper right of the back tells you what is inside.