Wadōkaichin

Wadōkaichin (和同開珎), also romanized as Wadō-kaichin or called Wadō-kaihō, is the oldest official Japanese coinage, first mentioned for 29 August 708[1] on order of Empress Genmei.

In February 2015 Japanese archeologists discovered ritual jars filled with wadōkaichin and jingō kaihō (神功開寳) cash coins at the Tehara ruins in Rittō, Shiga Prefecture.

[citation needed] The jars were placed there as a part of a Buddhist ritual, which indicates that the site was likely a government office or the resident of an important local.

[citation needed] On August 17, 2015 four wadōkaichin cache coins were discovered at the East Pagoda of Yakushi-ji, Nara during a restoration.

[6] According to the experts, this discovery at the Yakushi-ji is the oldest known example of the ancient Japanese practice of burying a cache of widely-circulated coins to purify a construction site anywhere in Japan.