Yu's ANALYSIS OF CURRENCY 885sary function as a medium of exchange. He was willing to concede that if the
peasants were, in fact, devoting all their time to the production of coins, it would
be justified to abolish its use, but he argued that in fact the peasants were keep-
ing to agriculture, and the artisans were engaged in making utensils even with
cash in the economy. The rulers maintained control over currency to maintain
the exchange of goods, and the use of coins reduced transportation costs in
exchange transactions and allowed more grain and cloth to be consumed. "This
was why cash carried on the tradition established by the use of tortoise and cowry
shells [in ancient times] and has never been abolished since."
Yu also quoted Chung Yu, who had also argued that grain and cloth were by
no means superior to cash as media of exchange because both those materials
could be debased as easily as metallic cash. He asserted that the adulteration of
grain and cloth was so pronounced in the Wei dynasty that severe punishments
were useless in controlling it, and cash areas seemed to prosper over regions
that used grain and cloth for money. Because of the adverse affects of the replace-
ment of cash with grain and cloth in Emperor Ming's era (227-40) almost every-
one at court favored the restoration of cash, and the emperor approved it. 13
Further corroboration to this point of view was provided by Chuang Kuei, a
regional official on the western frontier of the Western Chin dynasty, who estab-
lished a base where Kansu Province is today from 306 to his death in 314. Gov-
erning an area where the barbarian invasions had set the economy back to a more
primitive level, Chuang was able to achieve prosperity by fostering trade with
non-Chinese peoples beyond the frontier, and he adopted the suggestion of his
chief of staff, So Fu, to restore the use of the five-shu coin of the Han era to
facilitate this goa. 14 Yu must have admired this account because it corroborated
the view expressed in previous centuries that the minting of cash was bound to
create prosperity by increasing the circulation of goods in the market.
The Spread of Copper Cash to the Barbarians. Yu also believed that an impor-
tant but humiliating lesson for the Koreans of his own time was that non-Chi-
nese peoples, usually regarded as the barbarians of the world by enlightened
Confucians, had understood and mastered the use of cash as a medium of
exchange, leaving the Koreans even farther behind on the scale of world devel-
opment. He found references to the use of cash in the period of division after
the fall of the Later Han and in several states in the so-called Western Region
to the west of the Han boundary. The state of Shu (present day Szechwan) minted
iron cash, and several states in the Western Region used silver cash with designs
and likenesses of rulers on the face.
Yu was impressed by the widespread use of cash even beyond the confines of
China, but he was not ready to admit that any and all media of exchange beyond
grain and cloth were acceptable. He pointed out that iron cash had been aban-
doned because it was too heavy, and the paper money (chiao-fzu) of the Sung
dynasty in the I041 -49 period was simply "evil," but he praised copper and tin
for being the most suitable materials for minting cash. He lauded the Khitan,