Japan made coins from 8th century. The silver
slug known as mameitagin was made in 1736 to 1820. A crude slug silver,around
30-40% silver content, stamped with official valuation by local Ginza mint Shogun.
The first coin was minted in 1871 and this one-yen coin was made
from silver. From 1940 brass was used due to silver shortage during the war
years.
In 1868 Japan made rectangular shape coin that has been
popular with western coin dealers and collectors. The Meiji Dynasty NiBukin
gold coin.
This coin was 3 grams and gold content was 22.93 percent and
balance silver.
In 1854 silver bars rectangular shape were made known as Kaei
Ansei Isshugin and were 98.71% silver
This coin was the end of the Shogun power base as people
started to enjoy the round coins from western countries.