20 Sen Pattern

Pattern coinage from Meiji-era Japan occupies an unusually well-documented corner of numismatics, largely because the mint at Osaka kept meticulous records of experimental strikes. This piece likely dates to the transitional period when Japan was actively retooling its coinage system under Western advisors, testing alloy compositions before committing to production specifications. The billon formula here — with nickel added to the silver-copper mix — suggests a cost-reduction trial, not a metallurgical accident.

No 20 sen denomination in this composition ever entered circulation.