The is the largest denomination of Japanese yen coin issued for circulation. These coins were first struck in 1982 as the vending machine industry needed a higher valued coin for use in their machines. The denomination had previously been issued as paper currency which co-circulated with the new coins until 1994. Originally the 500 yen coin was made up of cupronickel, but was later changed to nickel brass, and then to bi-metallic to deter counterfeiting. This illegal practice has been a constant issue since the coin was first released due to its high purchase value. With a history spanning 3 imperial eras, 500 yen coins are also collectibles. History Cupronickel yen The 500 yen coin was first minted in 1982 as another coin denomination was needed for use in vending machines. The obverse of the cupronickel based 500 yen coin features a paulownia crest, while the reverse is designed with bamboo and Tachibana. These elements were chosen as they are regarded as symbols of good luck and people were already familiar with seeing them on the 500 yen notes. The diameter of the coin was set at 26.5 mm with a measured thickness of 1.85 mm. The inscription "NIPPON 500" was placed on the rim. As with other denominations created in the post World War II era, the newly issued coins circulated concurrently with their paper money counterparts. When the 500 yen coin was placed into circulation it acted as a replacement for the bill, which became supplementary currency. The 500 yen bill was phased out in 1984 in favor of the new coins, co-circulation continued until 1994 when the bills were withdrawn from circulation. Towards the end of Emperor Shōwa's (Hirohito's) reign mintage figures fell for the 500 yen coin. An all time low came when only 2,775,000 coins were minted in 1987 (year 62). The production of cupronickel 500 yen coins ended in 1999 due to incidents of counterfeit coins being used to rig vending machines. Nickel-brass yen The 2nd design for the 500 yen coin currently used today was first minted in 2000 with new anti-counterfeiting devices. Nickel brass was used as a replacement for cupronickel giving the coins a slightly golden appearance in comparison. This metallic change made it easier for vending machines to tell the difference between genuine versus counterfeit coins. The weight of the 500 yen coin was lowered from 7.2g to 7, and