From the establishment of the Bank of Korea in 1950 until the Second Currency Reform in 1953
After being established in 1950, the Bank of Korea put Bank of Korea notes into circulation along with those already in circulation at the time. As the North Korea circulated Bank of Joseon notes, however, the Bank of Korea had an emergency decree issued by the President designating its banknotes as the sole legal tender and promoting the unification of the currency system.
The Bank of Korea was established on June 12, 1950 in accordance with the Bank of Korea Act. Once established, it took over the Bank of Joseon notes (100-, 10-, 5-, 1-won and 20-, 10-, 5-jeon notes) and the Japanese government's subsidiary money (1-jeon coins), and on July 22, 1950 (during the Korean War), the Bank issued 1,000- and 100-won notes, the first Bank of Korea notes, and brought them into circulation together with the Bank of Joseon notes. As North Korea unlawfully circulated the Bank of Joseon notes during the war, under an emergency presidential decree on the exchange and circulation of Bank of Joseon notes on August 28, 1950, the Bank of Korea provided for the exchange of the Bank of Joseon notes for the Bank of Korea notes, which took place on five occasions up until January 16, 1953, and prohibited the circulation of Bank of Joseon 100-won notes. To promote convenience in transactions, the Bank of Korea issued banknotes in new denominations ― 500-won and second-design 1,000-won notes ― on October 10, 1952.