What is the currency of Japan?

Japan's currency is the yen, introduced in 1871 as part of the Meiji reforms that pulled the country into modern international trade. It replaced a chaotic system in which feudal domains issued their own paper notes alongside gold and silver coins of varying weight, and the new decimal unit was deliberately modelled on the silver dollars then circulating in Asian ports. The name comes from a word meaning round, describing the shape of those coins as against the older oblong and irregular pieces. In everyday use the yen has no working subunit; prices are quoted in whole yen, so a coffee costs several hundred and a train ticket a few thousand, which surprises visitors used to smaller numbers. The sign is a Y crossed by two horizontal strokes. The crossed-letter convention is common to several currencies, marking a plain letter as a monetary symbol.

Yen, yuan and won all descend from the same character meaning round.