Japanese yen
Currently circulating coinage

The obverse side of all coins shows the coin's value in kanji characters as well as the country name (through 1945, Dai Nippon (大日本, "Great Japan"); after 1945, Nippon-koku (日本国, "State of Japan") (except for the current 5-yen coin with the country name on the reverse). The reverse side of all coins shows the year of mintage, which is not shown in Gregorian calendar years, but instead in the regnal year of the current emperor's reign, with the first year of an era called gannen (元年). Imperial portraits have never appeared on Japanese coins, as the image of the emperor remains sacred.

In 1897, the silver 1 yen coin was demonetized and the sizes of the gold coins were reduced by 50%, with 5, 10 and 20 yen coins issued.

After the war, brass 50 sen, 1 and 5 yen were introduced between 1946 and 1948. The current-type holed brass 5 yen was introduced in 1949, the bronze 10 yen in 1951, and the aluminum 1 yen in 1955.

In 1955 the first unholed, nickel 50 yen was introduced. In 1957, silver 100 yen pieces were introduced, followed by the holed 50 yen coin in 1959. These were replaced in 1967 by the current cupro-nickel 100 yen along with a smaller 50 yen.

In 1982, the first cupronickel 500 yen coin was introduced. Alongside the 5 Swiss franc coin, the 500 yen coin is one of the highest-valued coin to be used regularly in the world, with a value of US$4.42 as of December 2016. Because of its high face value, the 500 yen coin has been a favorite target for counterfeiters, resulting in the issuance in 2000 of the second nickel-brass 500 yen coin with added security features. Continued counterfeiting of the latter resulted in the issuance in 2021 of the third bi-metallic 500 yen coin with more improvements in security features.

Due to the great differences in style, size, weight and the pattern present on the edge of the coin they are easy for people with visual impairments to tell apart from one another.

Commemorative coins have been minted on various occasions in base metal, silver and gold. The first of these were silver ¥100 and ¥1,000 Summer Olympic coins issued for the 1964 games. The largest issuance by denomination and total face value were 10 million gold coins of ¥100,000 denomination for the 60th anniversary of reign of the Shōwa Emperor in 1986, totalling ¥1 trillion and utilizing 200,000 kg fine gold. ¥500 commemorative coins have been regularly issued since 1985. In 2008 commemorative ¥500 and ¥1,000 coins were issued featuring Japan's 47 prefectures. Even though all commemorative coins can be spent like ordinary (non-commemorative) coins, they do not normally circulate, and ¥100,000 coins are treated with caution due to the discovery of counterfeits.

The 1 yen coin is made out of 100% aluminum and can float on water if placed correctly.
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