Korean currency
The yen was the currency of Korea during the Colonial rule, from 1910 to 1945, and was issued by the Bank of Joseon It was equivalent to the Japanese yen and consisted of Japanese currency and banknotes issued specifically for Korea. It was replaced by the South Korean won at par in 1945, and by the North Korean won in 1947.
Economy of North Korea
In 1979, North Korea renegotiated much of its international debt, but in 1980 it defaulted on its loans except those from Japan. By the end of 1986, hard-currency debt had reached more than US$1 billion. It also owed nearly $2 billion to communist creditors, principally the Soviet Union. The Japanese declared North Korea in default. By 2000, taking into account penalties and accrued interest, North Korea's debt was estimated at $10–12 billion. By 2012, North Korea's external debt had grown to an estimated US$20 billion despite Russia reportedly writing off about $8 billion of debt in exchange for participation in natural resources development. Besides Russia, major creditors included Hungary, the Czech Republic and Iran.