This medal was made to celebrate the 20th (1975) anniversary of the Chongryon (North Korean community in japan). There should be arround 200 000 of these worlwide as thats the member ship of the congryon. However there are likely less than that as the institution likely had less members. According to invaluable the medal also contains details in silver and is rare (https://www.invaluable.com/auction-lot/north-korea-chongryon-foundation-20th-anniversary-172-c-d324b07a0b).