CHAPTER 23
Copper Cash and the
Monetary System
Kim Yuk, the leading protagonist of the extension of the taedong system, was
also the leading advocate of the adoption of copper currency in the mid-seven-
teenth century, and Yu Hyongwon was sufficiently influenced by his ideas to
propose collecting part of national taxes in cash under his own plan for restruc-
turing national finance on the basis of the taedong system. Since copper cur-
rency became an important medium of exchange in the Korean economy in the
late seventeenth and eighteenth centuries, and the development of metallic cash
has been seen as one of the signs of a growing market economy and the begin-
ning of Korea's modem development, Yu has been perceived as one of the intel-
lectual pioneers of modernism.
Since copper cash disappeared from the market in the middle of the sixteenth
century, its reemergence in the mid-seventeenth century should be considered
both consequence and cause of commercial development in the economy. The
mechanics of the process of commercial development, however, are quite dif-
ficult to verify by quantitative measures. There is a marked lack of evidence
despite a host of scholars who have been asserting the growth of surplus pro-
duction in the agricultural economy from the late fifteenth century.
By the late fifteenth century Korean peasants had begun to switch from broad-
cast seeding of dry fields and the use of the fallow system to wet-field rice agri-
culture, and the application of fertilizer to permit yearly cultivation, methods
associated with the Chiang-nan or southern region of China during the Sung
period. Attempts by the government to copy Chinese and Japanese versions of
the water wheel for irrigation failed by 143 I, but by the late fifteenth century
irrigation was expanded from small-scale damming of upland streams to more
costly redirection of water from downstream rivers through barriers and gate-
ways into lowland sluices. Yi T'aejin argued that as production ofland expanded,
the established capital officials, royalty, and consort relatives used the local
Yuhyangso to mobilize peasant labor for the construction not only of irrigation
facilities but for the reclamation of land along the coastal regions to increase their
own private estates. The spread of irrigation also brought with it the benefits of
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