[4] King Sukjong of Goryeo created a new monetary system based on round copper-alloy coins with square holes as well as the ŭnbyŏng (銀瓶, 은병) shaped like the Korean peninsula.

The coins were produced bearing the inscriptions 東國 (동국/Dong guk or "Eastern Country"), 海東 (해동/hae dong or "East of the Sea"), and 三韓 (삼한/Samhan).

An extremely rare variant of the Samhan Tongbo (삼한통보, 三韓通寶) cash coin exists that bears the character 叁 written in "official script" instead of 三, of which only 2 have currently been found.

[3] These ŭnbyŏng were produced from the year 1101 and were engraved with an official state seal to mark them as a legitimate currency which was valid throughout Goryeo.

The ŭnbyŏng weighed around one Kŭn (斤, 근) which is roughly equal to 600 grams, this made them very useful for paying for large transactions.

[6] During the early years of the Joseon period cloth and grains would remain the most common forms of currency among the Korean people, during this time cotton was considered to be the most important medium of exchange.

[4] Another factor that led to the more widely adoption of coinage by the Korean people this time around was the fact seasonal problems such as droughts or less productive harvests made it more difficult to manufacture grains and cloth causing them to decrease in circulation.

The brisk production of goods to be traded and the subsequent development of commerce led to there being a relatively stable currency system during this era.

[10] These new markets and the merchants that they brought with them substantially raised the importance of currency, cash coins were now highly valued due to their ease of transportation and storage.

[5] On the right side of the square centre hole were the Chinese characters "一錢" (일전, il jeon), indicating its nominal value.

[5] Other variants of the 1 jeon Joseon Tongbo cash coins can have some slight variations in the method that the "head" (or top part) of the Chinese character Tong (通) is written.

It is generally believed that the Shibjeon Tongbo is a series of privately issued cash coins which is supported by the extreme diversity between specimens.

[5] Unlike earlier minted coins from the Georyo period, no mun currency produced under the Joseon dynasty bore the inscription Wonbo (元寶, 원보) on any large denomination because a Chinese naming taboo where the character "元" (Hangul: 원) may not be used as it was a part of Hongwu's original name, the founding emperor of the Ming Dynasty, of which Joseon was a tributary state.

[4] The generally low value of small denomination Sangpyeong Tongbo cash coins is also the origin of the common Korean phrase "Give me one pun!

[24] Most Sangpyeong Tongbo cash coins tend to be cast of high quality and have a yellowish colour and very clearly written Chinese characters, these were usually produced earlier at one of the 52 government mints,[5] while later less refined Sangpyeong Tongbo cash coins with rather crude appearances with a blackish colour and less well defined Chinese characters tend to be later made privately issues versions.

[12] The denominations of the Sangpyeong Tongbo cash coins were known as the Dangiljeon (當一錢), Dangijeon (當二錢), dangojeon (當五錢), and Dangbaekjeon (當百錢) based on their value.

[25][26][5] There are 3,078 varieties of the 1, 2, and 5 mun denominations, and 48 varieties of the 100 mun denomination documented by the authoritative Korean coin catalogue (Hanja: 高麗朝鮮時代貨幣; Hangul: 고여조선시대화폐), while there are estimated more than 5,000 different variants of the Sangpyeong Tongbo coins cast in the history of its production spanning 258 years, with many variants of the series still undocumented.

[5] According to the numismatist Alan D. Craig the Bank of Korea once had 3,137 different variants of the Sangpyeong Tongbo cash coins in its collection.

This eventually lead to traders preferring silver foreign currency such as the Mexican peso, Japanese yen, Russian ruble, and Chinese sycees.

[12] Both the Danbaekjeon and the Dangojeon cash coins were symptoms of the considerable turmoil that were occurring within the royal family and its advisers during the reign of King Gojong.

[49] While most of these were Hanja characters, some also had dots, circles, crescents, and horizontal lines which were used to represent things like the stars (星), the sun (日), the moon (月), and man (人).

[5] There are also a vast number of miscellaneous Hanja characters found on the reverse side of Sangpyeong Tongbo cash coins of which their meaning or what they represent is currently not known.

[5] The first issues were made from silver and lacked the iconic square centre hole designs of earlier and contemporary Korean coinages.

[5] During this period the Central Government Mint (典圜局, 전원국) created a machine-struck brass Sangpyeong Tongbo cash coin with a round centre hole.

[12] When Korea opened up its port cities to trade with Japanese businessmen following the Japan–Korea Treaty of 1876, it became apparent that the small denomination Sangpyeong Tongbo cash coins were not convenient at all for doing business which require larger transactions to take place, this inspired the creation of a new series of coinage made from silver.

[12] All of these coins had the characters "大東" (대동, dae dong, literally translated as "the Great East" which was one of the alternative names of Korea) in their obverse inscriptions.

[5] It became a huge issue when the yangban nobility started hoarding these coins for export at a profit,[5] where they were melted and recast as "horse hoof silver" (馬蹄銀) ingots.

[5] Half a decade after the issuing of the Dae Dong coins, between the years 1886 and 1888 (starting from "開國 497", or Kaeguk 497), the Korean government mint in Seoul (京成典圜局, 경성전환국),[5] which was opened in November 1886 at the Namdaemun,[12] began producing a minor number of machine-struck coins denominated in mun (文, 문) and hwan ("warn", "whan" 圜, 환).

[58][12] But as the German technicians were soon proven to be too expensive for the Korean government, they were replaced with employees from the Japan Mint in Osaka only a year later in 1887.

[12] The government exchange office prepared notes which would function a type of receipt until the withdrawn Korean mun coins could be re-minted, but these banknotes were never issued.