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.
North Korea–Russia relations
In May 2014 Russia and North Korea have agreed to settlements in rubles in all trade between the two countries. The first transactions in rubles between Russia and North Korea were carried out in October 2014.