**** Japanese 500JPY coin ****
500 yen coin has some secrets. "500 yen" in zero and hidden word "NIPPON".
In 20th century, a certain country had issued coins with almost same size and weight as Japanese 500 yen coin (previous version). Japanese Government requested the country to stop issuing the coin bu they refused. The foreign coin had been used to tease Japanese vending machines.
Therefore, Japanese government developed new version of 500 yen coin with high security.