13. What is "Premium Coin"?
The premium coin is a commemorative coin, made of precious metal, and is sold by the government at a price above the surface denomination.
The first one issued in Japan was the memorial gold coin of the Winter Olympic Games in Nagano.
For accuracy and nuances, see Japanese original.
The law concerning a unit of currency, issuance of coinage and so on (1982, law, No.42)
Article 10 The Japan Mint sells coins authorized by the finance minister stipulated below.
1 The commemorative coin whose material includes precious metal, and whose production cost exceeds its surface denomination.