1 Mon 'Gentsūgenpō'

Gentsūgenpō (元通元寶) was one of the Chinese-style cash coins imported into Japan in enormous quantities during the Muromachi period, when the chronic domestic shortage of bronze coinage forced Japanese merchants and the bakufu alike to rely almost entirely on Song, Yuan, and early Ming imports. Japan had no functioning copper coin mint of its own during these centuries. The coins circulated so freely, and were trusted so completely, that private merchants began issuing their own selection criteria — the so-called *erizeni* disputes, where certain worn or substandard pieces were rejected outright, causing repeated legal crises the Ashikaga shogunate proved wholly unable to resolve.