The Japanese Yen is official currency of Japan. It is the 3rd most traded currency in the world behind the USD and EUR. The ISO-4217 is JPY.
The New Currency Act of 1871 introduced Japan's modern currency system, with the yen defined as 1.5 g of gold, or 24.26g of silver, and divided decimally into 100 sen or 1,000 rin. It replaced the previous Tokugawa coinage as well as the various hansatsu paper currencies issued by feudal han (fiefs). The Bank of Japan was founded in 1882 and given a monopoly on controlling the money supply.