Japanese mon (currency)
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.
[12][13] Bitasen refers to the Shichūsen [ja] 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.
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 were not 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.
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 Shogunate, however, opened up the seaport of Nagasaki to export with the Dutch East India Company and Chinese merchant ships from Southeast Asia.
[20][21] 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 was not accepted for its nominal value.
[24][25] 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.
