Japanese mon (currency)

An Eiraku Tsūhō (永樂通寳) coin, one of the most commonly circulating coins of the era before the Edo period.

The flag (Nobori) of Oda Nobunaga displaying Chinese Eiraku Tsūhō coins.

Though the production of copper, silver, and gold coins had already started in the eighth century, they weren't often used as a medium for exchange until later when the Japanese started importing Chinese coins, which replaced the Japanese commodity currency economy. As internal trade grew due to agricultural and handicraft developments, the people started preferring coinage to barter, leading to a growth of demand for copper coins.[4] The Southern Song dynasty prohibited the export of its coinage in 1179 due to its problem with the outflow of currency, but shiploads of Chinese coins would still enter Japan annually through Ningbo.[5][6] There is evidence to suggest that the Yuan dynasty used to extensively export Chinese cash coins to Japan for local circulation. The Sinan shipwreck, which was a ship from Ningbo to Hakata that sank off the Korean coast in the year 1323,[7] carried some 8,000 strings of cash coins,[8] which weighed about 26,775 kilograms (59,029 lb).[9]

Since the trade had begun with Japan, and they received payment in Chinese coins for Japanese goods, they stopped minting their own copper coinage until 1587. The Ashikaga shogunate imported Kōbu Tsūhō (洪武通寶), Eiraku Tsūhō (永樂通寳), and Katei Tsūhō (嘉靖通寶) from the Ming dynasty, which they referred to as Toraisen (渡来銭) or Minsen (明銭),[10][11] but the high demand for copper coinage inspired local and private production of copper coins (Shichūsen, 私鋳銭). An example of a Shichūsen used for trade with China and the Ryukyu Kingdom would be a Kōbu Tsūhō coin minted by Satsuma domain which included the character "治" (Ji) on the reverse indicating that it was minted at the town of Kajiki, while still using the inscription of the Hongwu Emperor of Ming China. Some Shichūsen would also bear the inscriptions of coins from the Song dynasty, although it was not uncommon for many coins to simply be recasts and copies of older Song and Ming dynasty coins in the form of Iutsushi (鋳写し) or by simply adding extra carvings on existing circulating Chinese coins.[12][13]

Bitasen refers to the Shichūsen coinage produced in Japan by the nobility and private local mints, and not by the imperial government or before the establishment of the Tokugawa shogunate which were often poor in appearance, as well as damaged and worn out imported Chinese coins.[14][15]

Over time these coins would become damaged, and this made sellers more discriminating in what coins they would accept at face value, often accepting them only at ¼ of a good quality coin. Though Chinese coins would continue to circulate in Eastern Japan, the confusion and chaos caused by the Bitasen coinage caused rice to replace copper coinage in Western Japan.[16] From 1608 onwards it was illegal to pay with Bitasen, and the shogunate opened more mines for the production of copper, silver, and gold coinages.[17][18][19][20][21] Despite this, however, Bitasen continued to circulate within Japan, but from 1670 the Eiraku Tsūhō was completely prohibited from circulation and depreciated in favour of the Kan'ei Tsūhō.[22]

In 1636, the Kan'ei Tsūhō (Kyūjitai: 寛永通寳 ; Shinjitai: 寛永通宝) coin was introduced by the government of the Tokugawa shogunate as a means to standardise copper coins and keep up a sufficient supply of copper coinage, being the first government minted copper coin in 700 years, despite this however they were introduced in the Mito domain 10 years prior during the 3rd year of the Kan'ei era. These coins would become the daily currency of the common people and would be used for small payments.[23][24][25] Due to the isolationist policies of the Tokugawa shogunate, the outflow of currency halted and Kan'ei Tsūhō coins would continue to stay the main coin circulating in Japan. Kan'ei Tsūhō were minted for 230 years despite the fact that the Kan’ei era ended in 1643, and coins would continue to bear the Kan’ei legend, even when a new denomination of the coin was introduced a century later, though they weren't all uniform as the shogunate outsourced the mintage to regional and local merchants who would cast them at varying weights and sizes, as well as occasionally having local mint marks. By the 1650s 16 private mints were opened for the production of Kan'ei Tsūhō coins all over Japan.[26] Kan'ei Tsūhō produced before 1688 are referred to as "old Kan’ei" and are recognisable by their similar calligraphic styles making them hard to differentiate from one another, meanwhile Kan'ei Tsūhō coins produced after 1688 (or "new Kan’ei" coins) tend to be more diverse in calligraphic styling, and the 4 mon denomination has waves on its reverse making it easily distinguishable from other coins.

From 1738 the government authorised the manufacture of iron Kan'ei Tsūhō 1 mon coins, and in 1866 (just before the end of the Edo period) iron 4 mon Kan'ei Tsūhō were authorised. While iron coins were being minted, the quality of copper coins would decrease due to frequent debasements.

As Bitasen coins were no longer allowed to circulate within Japan, Japanese traders started selling them on foreign markets for profits, especially on the Vietnamese market where a huge influx of Eiraku Tsūhō and Kan'ei Tsūhō coins from Japan made the Japanese mon the de facto currency of the region. The large export of Japanese coins to Vietnam during this period mostly happened on Red seal ships.

From 1633 the Tokugawa government adopted the isolationist Sakoku policy. The Shogunate, however, opened up the seaport of Nagasaki to export with the Dutch East India Company and Chinese merchant ships from Southeast Asia. The Japanese merchants who were now prohibited from exporting mon coins directly to Vietnam used the Dutch traders as middlemen and exported, between 1633 and 1637, around 105,835 strings of 960 Eiraku Tsūhō and Kan’ei Tsūhō coins (or 101,600,640 mon) to Vietnam. From 1659 this continued with the Nagasaki trade coins which were specifically minted for foreign markets; this is why they were escribed with Song dynasty inscriptions as coins from the Song dynasty were already circulating in Southeast Asia and the populace had already become accustomed to them. The trade of mon coins stopped however after the Shogunate banned the export of copper in 1715.[27][28]

A Hōei Tsūhō (寳永通寳) coin, these were unsuccessfully introduced as a large denomination 10 mon coin in 1708, but failed because of their debased copper content.

A Tenpō Tsūhō (天保通寳 - 當百) coin of 100 mon, with the Kaō of the Kinza mint's Gotō San'emon.

In 1708 the Tokugawa shogunate introduced the Hōei Tsūhō (Kyūjitai: 寳永通寳; Shinjitai: 宝永通宝) which had a face value of 10 mon (but contained 3 times as much copper as a 1 mon Kan’ei Tsūhō coin), which lead to the coin being discontinued very shortly after it started circulating as it wasn't accepted for its nominal value.[29]

However, in 1835 (during the Bakumatsu) the Tokugawa shogunate tried issuing a larger denomination copper coin again with the Tenpō Tsūhō 100 mon coin which this time only contained five and a half times the amount of copper in a 1 mon coin,[30] but was accepted nonetheless. The introduction of this denomination caused large scale inflation comparable to that of caused by the 100 wén coin minted by the Qing dynasty in 1853, or the 100 mun coin issued by the Kingdom of Joseon in 1866.[31][32] The reason for the change in mentality was the scarcity of copper which had earlier forced the Japanese to mint iron coins breaking the previously established tri-metallic system. The concurrent circulation of 1, 4, and (heavily debased) 100 mon coins caused for a chaotic reaction from the market, as did widespread circulation of forged coinage.[33]

Another major cause for inflation was that from 1859 local Daimyō started minting their own coinage often with high denominations to increase the money supply or to get more gold and silver for their low copper supplies. In 1862 this inspired Daimyō Shimazu Nariakira to produce Tenpō Tsūhō derivatives in the form of 100 on Ryūkyū Tsūhō coins and even ½ Shu Ryūkyū Tsūhō coins under the pretence of minting coins for their vassal Ryukyu Kingdom, this proved profitable for the Satsuma domain.[34][35]

• Chinese wen
• Korean mun
• Vietnamese văn
• Ryukyuan mon