It's helpful to remember that over its long history up until the Meji Restoration in the late 19th century, Japan was more a collection of individual fiefs or kingdoms than a single, organized nation-state. Appropriately, these various sections of Japan had their own forms of metal currency (called "specie"), typically based on the value of the constituting precious metals.
With the enactment of the New Currency Act of 1871, the government of the newly-forming nation-state of Japan instituted three rules for the national currency: gold coins would be the monetary standard, coins would be round-shaped and stamped out as in modern Western countries, and they would be valued according to a decimal counting system. Since that time, the gold standard has been abandoned, but the shape and decimal counting systems (though in modified form) have remained. The yen remains the standard unit of currency in Japan, with all units of money being counted in terms of yen. Older forms of currency, the sen and rin, were taken out of circulation by 1953.
Japanese used the gold standard of currency valuation and guarantee with the enactment of the New Currency Act in 1871. The value of the yen was thus "guaranteed" by the existence of gold in possession by the Bank of Japan. Like most modern economies, Japan abandoned the gold standard. Japan adopted a managed currency system in 1942 in order to have better control over the monetary policy and trade.
The Bank of Japan prints banknotes, or bills, in denominations of 1,000, 2,000, 5,000, and 10,000 yen. Coins are available in allotments of 1, 5, 10, 50, 100 and 500 yen. The current bills (the E series) carry the faces of historically significant scientists (1,000-yen note), artists (and, significantly, a woman) (5,000-yen note), and artist/politicians (10,000-yen note), and a famous historical site (2,000-yen note).
In Japan, the symbol for the yen is 円, pronounced as "yen," and meaning "a round object." The international exchange symbols for the Japanese yen are ¥ and JPY. Currently, the Japanese Yen is the third most-traded currency in the world currency exchange markets, after the U.S. dollar and the British Pound Sterling.
The Bank of Japan produces all the Japanese coins and bills in circulation. The Bank of Japan was founded in 1882 to, according to the Bank of Japan's website, "prevent an overissue of...currency and to stabilize its value". The Bank of Japan is Japan's central bank, setting monetary policy and interest rates.
