Rectangular gold and silver coinage was issued in Japan prior to 1870. In that year the great emperor Matshuito (Meiji) implemented a currency reform that incorporated the decimal system. Rectangular coinage issued prior to that time varied widely in fineness and weight despite occasional government efforts to implement a consistent standard for minting coins.

In addition to implementing currency reform, Meiji--sometimes known as Meiji the Great-- oversaw the beginning of the transformation of Japan from a backward feudal state to a highly industrialized modern world power. In less than 40 years the Japanese would challenge and defeat a large western power, Russia, in a great sea battle fought with modern armored ships.

ach coin can be identified to the reign of a specific ruler, although the date in most instances can only be determined by the period of the Emperor’s rule.