I had to turn my phone sideways to read the coin it says 常平通寶. 常平通宝 Changping tongbao coins were issued in the 朝鲜古代 chaoxian dynasty which was in Korea. In fact in Chinese, North Korea is called chaoxian 朝鲜. The dynasty lasted from 1392-1910. The changping coins were minted starting in 1633.