The first Ryukyuan coins to circulate were the Taise Tsūhō in 1454 under the reign of KingShō Taikyū; the second were the Sekō Tsūhō which were first minted in 1461 under the reign of King Shō Toku. Though the Taise Tsūhō are considered the oldest Ryukyuan coins, there are possibilities that an older version of the Chūzan Tsūhō was cast between 1321 and 1395 by the Kingdom of Chūzan, though these possible coins should not be confused with a later Chūzan Tsūhō cast under King Shō Kō. Both the Taise Tsūhō and Sekō Tsūhō were modelled after the Ming dynastyEiraku Tsūhō, a coin manufactured en masse for foreign trade. Because copper shrinks when it cools, the Sekō Tsūhō was smaller than the Chinese Eiraku Tsūhō. The Sekō Tsūhō was originally cast to make up for a shortage of currency often attributed to reckless politics and high government expenditure, such as the expensive invasion of Kikai Island by King Shō Toku in the 1460s. Coins issued by the Ryukyu Kingdom:
Inscription
Kyūjitai
Shinjitai
King
Dynasty
Image
Taise Tsūhō
大世通寳
大世通宝
Shō Taikyū
First Shō
Sekō Tsūhō
世高通寳
世高通宝
Shō Toku
First Shō
Kin'en Sehō
金圓世寳
金円世宝
Shō En
Second Shō
Chūzan Tsūhō
中山通寳
中山通宝
Shō Kō
Second Shō
Despite the small size of the Ryukyu Kingdom, the coins from this era are not uncommon and have been known to be regularly found on the Indonesian islands of Java and Sumatra due to the international nature of these coins and the success of Ryukyuan maritime trade. After the issuance of the Kin'en Sehō in 1470, the Ryukyu Kingdom stopped manufacturing their own mon coins and imported Chinese currency as the main medium of exchange. As no official records exist of the production of these coins it is sometimes taken into doubt that these coins were actually produced by the Ryukyu Kingdom.
Denominations after 1862
100 mon (琉球通寳 – 當百)
The 100 mon Ryūkyū Tsūhō coin was an ellipse-shaped coin modeled after the Japanese Tenpō Tsūhō coin of the same denomination. Like the Tenpō Tsūhō, its face value was placed at 100 mon but its weight was merely 6 to 7 times that of a 1 mon coin. Despite this, Satsuma Domain ordered that it would circulate at the value of 124 mon, which made it a profitable coin to manufacture, but this made the coin unpopular in circulation. The 100 mon was first manufactured by the government of Satsuma in Kagoshima City from 1862 for circulation within the Ryukyu Islands as well as in the Satsuma Domain itself, but started to circulate in Japan's other provinces soon after their production. Coins minted in Kagoshima bear the mark of the katakana character "sa" on the left and right flat edges of the observe, which signifies that the coin is from Satsuma Domain.
Half Shu (琉球通寳 – 半朱)
The half Shu denomination was a round coin with a square hole introduced alongside the 100 mon by Satsuma, which ordered it to circulate at the value of 248 mon despite it weighing only 10 to 12 times the weight of a single mon coin. The word Shu is a Japanese unit of measurement used with gold currency, indicating that the Satsuma government was trying to fix the exchange rate between the copper mon coins and gold currency such as the Koban. Officially, one half Shu would mean 32 coins would have the value of one Ryō, though this conversion rate seems unlikely to have occurred in practice. The production of these coins was set up by DaimyōShimazu Nariakira in order to rebuild Satsuma's economy; in total, around one million Ryō worth of Ryukyuan coins were minted from 1862 to 1865.