debuted it was and still is the highest valued coin in the world depending on exchange rates. In comparison the coin's purchase power was about double that of a two-pound coin (UK) in 2012. These reasons have made 500 yen coins a prime choice for counterfeiters ever since they were first minted in 1982. Problems arose that year as South Korea introduced a coin worth 500 won (₩500) valued at about one tenth of the value of the 500 yen coin. Both coins are made up of the same cupronickel alloy and have the same 26.5 mm diameter. It did not take long before these coins were modified to be the exact weight of the 500 yen coin, nor was it difficult. Counterfeiters would use them as slugs by drilling small holes on the surface of the coin to reduce their weight and fool vending machines which relied on weight to identify the coins. The large gap in value between the two coins meant that these thieves could make a good profit. By the 1990s vending machines full of these foreign coins had become a serious issue which dealt losses to the vending machine businesses and beyond. By the end of the decade 70% of the 5.5 million vending machines in Japan had stopped taking the coin. This did not deter counterfeits as between January and October 1999 police found 657,000 altered coins. The Japan Mint responded to these incidents beginning in 2000 with a new nickel brass based 500 yen coin featuring anti-counterfeiting devices. When viewed at different angles "500円" is either printed vertically in each zero, or a bar can be seen running down the inside of each zero. Microprinting reading "Nippon" is also found on both the obverse and reverse of the coin. Vending machines were then adapted to reject the old cupronickel 500 yen coins. This was done by having the machines only recognize the conductivity given off by the nickel brass used in the new coins. These second generation nickel brass coins were soon counterfeited as well by using raw materials. In 2005, an article in The Japan Times reported that the perpetrators deposited the coins in an account using an ATM, the money was then withdrawn in the form of banknotes. The coins involved were made up of the same alloy as genuine coins but the percentage of the alloys used were different. By