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.
Mining in North Korea
North Korea is thought to have tremendous potential metal resources (and particularly rare-earth metals), which have been valued in excess of US$6 trillion by the South Korean national mining company. There is much investment from Chinese mining companies, with an estimated $500 million investment in the last 11 years. 41% of all Chinese companies trading in North Korea are involved in mining.