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.
South Korean won
The Bank of Korea is the only institution in South Korea with the right to print banknotes and mint coins. The banknotes and coins are printed at KOMSCO, a government-owned corporation, under the guidance of the Bank of Korea.
After the new banknotes and coins are printed/minted, they are bundled or rolled and shipped to the headquarters of the Bank of Korea. When delivered, they are deposited inside the bank's vault, ready to be distributed to commercial banks when requested.
Every year, around Seollal and Chuseok, two major Korean holidays, the Bank of Korea distributes large amounts of its currency to most of the commercial banks in South Korea, which are then given to their customers upon request.