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.
2017–18 North Korea crisis
Since North Korea's first nuclear test in 2006, the UN Security Council had passed a number of resolutions that imposed various sanctions on the DPRK, including restrictions on economic activity. Nevertheless, North Korea's gross domestic product grew by an estimated 3.9 percent in 2016, to about $28.5 billion, the fastest pace in 17 years; the progress was largely attributed to continued trade with China, which accounted for more than 90% of North Korea's international trade.