Eiraku-tsuho (bronze coins struck in the Ming dynasty) (永楽通宝)

Eiraku-tsuho is a coin minted during the reign of the 3rd emperor of the Ming dynasty, Yongle.

A huge number of the coins were imported into Japan during the Muromachi period and they were called Eiraku-sen and distributed in Japan up to the early Edo period. The coin was round-shaped which has a square hole at the center, and on the surface were kanji characters '永樂通寳' which are read from top to bottom and right to left. The coins were made of copper and circulated as a value of 1 mon (a unit name and value of small money at the time); however, in Japan one Eiraku-tsuho coin was valued at 4 mons of Bitasen (low quality coins with surfaces worn away) from the Tensho years.

In 1608, a ban on the circulation of Eiraku-sen was issued and Eiraku-tsuho were replaced with domestically minted coins such as Kanei-tsuho. However, the virtual monetary unit called Ei (Ei of Eiraku-tsuho) remained in place; i.e., Ikkanmon (weight of the coins and approximately equivalent to 1,000 mon of coins) of Ei equaled 1 ryo (a unit name for a large sum of money) of a gold coin, thus 1 Ei was treated as 1/1000 ryo. This Ei account system actually continued to be used for the collection of nengu (annual tax). Thus Eiraku-tsuho greatly influenced the Japanese monetary system over a long period of time (1 Ei was actually equivalent to around 4 mon).

It is thought that Eiraku-tsuho was not circulated in the territory of the Ming and was mainly used overseas. In the Ming dynasty during the reign of the founder Emperor Kobu (Shu GENSHO), the use of metal coins was prohibited and all the money were switched to paper money (later switched again to Ginjo - silver coins used in China until early in the 20th century).
(Emperor Kobu also issued Daichu-tsuho 'copper coins' in a part of his own territory before he unified China; after the unification, he issued Kobu-tsuho 'copper coins.')
In the meantime, the money economy in Japan rapidly developed and the demands for Chinese coins greatly increased. As a result in China, Eiraku-tsuho was minted as an instrument to settle the trade with Japan.

Nobunaga ODA used Eiraku-tsuho as his symbol. The reason why he used it as his symbol was not known, however, it is said that with foresight he paid attention to the monetary economy.

As commerce and physical distribution was activated from the Heian to the Kamakura period in Japan, the need for money became important. However, because the Ritsuryo system had already collapsed at the time and the technology to mint coins as well as the office in charge fell into disuse, Japan had to import copper coins from China to distribute domestically.

Among them, the copper coin Eiraku-tsuho (Eiraku-sen) minted from 1411 in the reign of the Ming dynasty's Emperor Yongle were imported on a massive scale in the middle of the Muromachi period. Most of them were imported through the tally trade (between Japan and the Ming dynasty) to Japan. The term Eiraku-sen is sometimes applied to all copper coins imported at the time of the Ming dynasty. The quality of the copper coins was good, and these coins were used as a key currency until the early Edo period.

While privately minted coins are called Shichusen, many shichusen minted in Jiangnan in China and Japan were also circulated. However, these shichusen were called bitasen for their inferior quality and exchanged at a lower value than government casting Eiraku-sen. As the difference in the value of the copper coins became a problem, the sengoku daimyo (Japanese territorial lord) in the Sengoku period often issued ordinances called Erizenirei, which banned differentiating the good coins and bad coins. The Edo bakufu (Japanese feudal government headed by a shogun) began casting their own copper coins (called Keicho-tsuho) in the year 1606 of the Edo period; two years later, the bakufu issued an ordinance prohibiting the distribution of Eiraku-sen. It is said that at this stage, the amount of Keicho-tsuho circulated was not sufficient enough, and the ban resulted in prohibiting the circulation of Eiraku-sen at a superior position and promoting the use of Eiraku-sen at the same level as bitasen. After the Genna-Enbu (peace after Genna era) in 1636, the bakufu minted Kanei-tsuho (pronounced as kan-ei-tsuho) in earnest and Eiraku-sen was gradually driven out when the new coins started to circulate in the entire country in and after the Kanbun era (1661- 1672).

The Eiraku-tsuho was mainly circulated in the Ise Province and Owari Province and eastward. Particularly in Kanto, Eiraku-tsuho was regarded as the key currency, and in some cases this is called Eidakasei (currency system based on Eiraku-tsuho). In Western Japan, people preferred using the old coins from the Tang and Northern Sung dynasties such as the Sung currency, and Eiraku-tsuho was not circulated very much until the 16th Century.