Ichibugin
The Ichibugin was a monetary unit of Japan towards the end of the Edo period. During their time in circulation each coin was worth of a gold Ryō, and could also be exchanged four silver or gold shu coins. The medium of exchange was later expanded to allow 3 Ichibugin for a United States or Mexican Silver Dollar. While no coins worth "3 bu" were ever produced by the shogunate, the corresponding coins were countermarked as such.