Koku

Invented and designed by Yasuki Tanaka in 243.

The design features are the kanji of the Fortunes on one side and the Kami on the other, and can be recognized as the design to this date.

The copper coin is simple and recognizable and confound most attempts at forgery.

In the beginning it was used extensively by the Crane Clan, but when the Emperor asked about the little copper coins he was given the minting plates as a gift.