Counterfeit 500 yen coins have been found in a consignment of mail sent from China, a Finance Ministry official said Friday.
This is the second batch of fake 500 yen coins discovered since a new version of the coin was introduced almost four years ago to thwart counterfeiting.
The 17 coins were identified as fakes by the Japan Mint after they were found by Tokyo Customs authorities, the official said.
The coins were made of the same materials used in genuine coins, although the metal levels were different, the official said, noting the fakes were also a slightly different shade and the embossments were unclear.
The newly discovered coins were more sophisticated than the counterfeits found in November. Those were made of a different metal.
"While we do not interpret the finding of the coins as an indication that our anticounterfeiting technologies have been breached, we cannot deny the possibility that these coins might be accepted by vending machines," the official said.
Japan introduced a new version of the 500 yen coin in August 2000.