THE NORTHERN SUNG DYNASTY (A. D. 960-1126) has come to be recognized as a period of rapid commercial and industrial development.' The reasons for eleventh-century Chinese economic growth are many and varied. But the currency system was an important aspect of the changes taking place during this era. The purpose of this paper is to outline the evolution of the basic monetary framework of the early Northern Sung economy. When Chao K'uang-yin established the Sung dynasty in 960, a bewildering conglomeration of iron, lead, and bronze coins of all sizes and alloys constituted the medium of circulation in the regions of China that would come under Imperial control during the next two decades. Since the eighth century, and possibly earlier, the Chinese money of account had been the (ch'iena). The term ch'ien can also mean, depending on context, a unit of weight, a coin, money in general, or a tax. It may also have a varying value as a money of account in different regions of China. Clarity requires a different translation of chrien for each of its uses. In this study, I have translated it as cash when used as a money of account, chien when used as a unit of weight, and coin when used to refer to the actual metal piece. To make matters more complicated, the cash's multiple, the string of one thousand cash, refers to a number of coins as often as it does to a unit of 1,000 for accounting purposes. Terminological distinctions are sometimes made, but our documents are by no means consistent.2 A means of devaluation was to issue the actual coins in of less than 1,000, and then cry up the strings to the value of a full 1,000 string. Where it has been impossible to determine whether a document refers to full of 1,000 coins or short tariffed at 1,000 cash, I have indicated alternative explanations and calculations in the footnotes. Otherwise, I have followed the same usage adopted for the term ch'ien.3 The most important coin during the T'ang dynasty was the K'ai-yiian t'ung-paob, an alloy of 83 percent copper, 15 percent lead, and 2 percent tin, weighing one ch'ien (3.73 grams),5 and tariffed at one cash. These coins were first issued in 620 A. D.6 and continued to be minted and circulated through the Five Dynasties (907-960 A. D.), supplemented in North China with issues of the same standard by the Later Han and Later Chou rulers.7 The monetary situation was far more