Mikami Y., with J. Batts
their use in the economic sphere.^12 There are in fact examples of mumon ginsen and raw silver ore
used as internment materials from the seventh through the eighth centuries, confirming their use
outside the realm of economic activity.^13 Although it is widely recognized that silver ore, at least,
performed a monetary role and circulated in classical society, it does not follow that the volume
in circulation was able to support commerce in its entirety.^14 Rather, in- kind currencies such as
rice, cloth, silk wadding, and salt were used as currencies in the practical economic exchanges of
the seventh century.^15 Even after the appearance of the Wadō kaichin in the eighth century the
monetary function of these commodities continued, although they had played a more prominent
role in commerce prior to the issuance of copper coins.
The Wadō kaichin struck in 708 was a new currency, introduced in addition to the in- kind
currencies circulating in this complicated fashion. It is thought that the coinage also served to
unify the complex measures of value resulting from multiple commodities of exchange. The
ritsuryō state issued the Wadō kaichin with an eye toward ensuring the financial resources necessary
for the upcoming relocation of the capital to Heijō-kyō (Nara) in 710. Afterward, the coins came
to circulate in and around the capital area as a currency supporting the people of the new city.
Coinage in the Nara period
According to the Shoku Nihongi, copper was discovered in the Chichibu district of Musashi during
the first month of 708 and presented to the court.^16 Full- scale casting of coins was initiated that
same year, following the establishment of an Office of the Mint (Jusenshi) the following month.
The new office first issued Wadō kaichin silver coins in the fifth month, followed by copper coins
in the eighth month.^17
The ritsuryō state placed a great deal of value on copper coins, as can be gathered from the
fact that the presentation of Japanese copper catalyzed the issuance of a coinage. Nevertheless,
the first coins minted were silver, not copper. There are various opinions as to the reasons for
this. Sakaehara Towao suggests that the silver coins served as an intermediary, allowing the
copper coins that followed to assume in turn the monetary function held by silver in previous
eras.^18 Tōno Haruyuki maintains that copper coins alone were insufficient, and that by leading
with silver coins the court increased the total value of currency in circulation.^19 In each of the
next two years, in the eighth month of 709 and again in the ninth month of 710, the court
issued prohibitions against the use of silver coins, and it is thought that the minting of copper
coins as planned and the sudden spread of counterfeit silver coinage together formed the back-
drop to these edicts.
As stated previously, an important reason that the ritsuryō state issued the Wadō kaichin at this
time was in order to bear the costs of construction for the new capital city, Heijō-kyō. Using
copper coins to cover the labor expenses for construction in turn made it incumbent upon the
court to ensure that their consumption and distribution in the area around the new capital pro-
gressed smoothly. At the same time, by endowing copper coins with a higher official value than
the copper ore from which they were made, the government sought to secure additional
profits.^20
In order to ensure that the Wadō kaichin circulated, the government needed to work scrupu-
lously to implement a policy toward that end. The court denoted a standard rate of exchange
with in- kind currencies such as rice and cloth, establishing six shō (approximately four to six
liters) of unhulled rice as equal to one copper coin in 711, and five coins as equal to one kida (about
four meters) of cloth the following year.^21 That same year, the government continued its program
of encouraging circulation through the promulgation of the Chikusen joi hō, a law allowing certain
court ranks to be purchased for set numbers of copper coins, thereby rewarding those who had