As wado (Japanese copper) was offered from Chichibu (Kuroya) in Musashi Province in 708, the Empress changed the name of an era into Wado and ordered the minting of Wado-kaichin coins.
708年に武蔵国秩父（黒谷）より和銅が献じられたので、和銅に改元し、和同開珎を鋳造させた。