Korean currency
In 1902, won was introduced as the official currency unit replacing yang at 1 won = 5 yang. The bank of Korea was established 1909 but soon after in 1910, Imperial Japan annexed Korean Empire. Under Colonial rule, the country was made to use the currency unit "yen" in the name of Korean yen, which took over the Korean won at par. After the division of Korea, the state of South Korea was established and recognized in 1948, and won was again made the official currency of the new state. "jeon" was made the subunit of the currency that divided it into 100 equal parts. Bank of Joseon issued the currency for independent South Korea for the first time that too in banknotes only.
North Korean won
As explained above, there are two varieties of foreign certificates. For the 1978 banknote series, foreign certificates, called "Pakkundon", meaning "exchangeable money" were implemented by an overstamp and serial number color. This was intended to protect the value of the national currency in North Korea's command economy. These were first released in 1983 in two forms, one for "socialist visitors" which had a red stamp, and one for "capitalist visitors" which had a green stamp. Another series was released in 1986 with either a blue or red Guilloché style stamp. These were issued in all denominations, except for the ₩100 note, presumably because it was assumed by the government that foreign visitors to North Korea would not show proper respect for its depiction of Kim Il-sung. These notes were discontinued in 1988 and replaced with a new series of Pakkundon in all banknote form that was more distinguishable and unmistakable from generic circulation currency.