Korean yen
The Korean yen was the currency of Korea between 1910 and 1945. It was equivalent to the Japanese yen and consisted of Japanese currency and banknotes issued specifically for Korea. The yen was subdivided into 100 sen. It replaced the Korean won at par and was replaced by the South Korean won and the North Korean won at par.
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.