Chinese cash coins: from molds to strings
Chinese cash coins were usually cast, with molten metal poured into molds rather than designs being struck onto individual pieces. Their characteristic form combined a round outer edge with a square hole in the center. Used from the fourth century BC until the twentieth century, this coinage began during the Warring States period and continued throughout Imperial China. Most pieces were copper or bronze alloys; iron, lead, and zinc appeared less often, while silver and gold examples were rare. Before 1505, bronze was typical, and from that year onward brass became the more usual material for these copper-alloy coins.
Early casting during the Zhou dynasty began with characters and the coin's outline carved directly into soapstone or clay molds. Workers placed mold sections together, positioned the core, and poured molten metal through an opening into the cavity. Without a prior model, pieces from the same series could differ because separate molds carried the inscriptions. During the Han dynasty, master bronze molds became a basis for making other molds, bringing greater consistency to circulating money. Early Ban Liang pieces were said to resemble wheels, while older forms of Chinese coinage resembled farm tools, including the spades and knives used as monetary tokens.
From the sixth century onward, mother coins provided the basis for another manufacturing method. These models were engraved in metals such as tin. Fine wet sand went into pear-wood frames, with coal and charcoal dust added to refine the process. A mother coin was placed on the sand, and another frame was positioned above it. A rod formed a separate entrance for the molten metal. After cooling, the connected metal formation was removed, leaving a "coin tree" from which individual pieces were detached. Workers then placed coins on long square rods and rounded their edges, often working on hundreds at once.
Mother coins could themselves be cast from hand-carved ancestor coins, a technique documented by a Yuan-dynasty example dated 1308–1311 in the National Museum of China. A single ancestor could produce tens of thousands of mothers, each capable of generating tens of thousands of circulating pieces. Chinese cash coins also reached a machine-struck phase during the late Qing dynasty. A machine-operated mint opened in Guangzhou, Guangdong, in 1889, producing the majority of the machine-struck cash. These machine-made pieces tended toward brass, and later reductions in copper content brought greater use of cheaper lead and tin, giving the coins a yellowish tint.
The central hole gave the finished pieces another practical role. Chinese cash coins could be threaded into strings representing higher denominations, an arrangement used frequently because individual coins had low value. A nominal string held 1000 coins, divided into ten sections of 100, but local custom changed the total. The person assembling it could retain a few coins as payment for the work. A string might therefore hold 970 pieces in one city and 990 in another. Such a string weighed more than ten pounds and was generally carried over the shoulder. Flying cash paper equivalents sometimes pictured coins strung together.
Traders and merchants accepted strings because counting each coin took too much time. Damaged pieces and inferior copper alloys could pass within strings that were accepted without inspection, so nominal value increasingly mattered more than weight. Professional stringers assembled sections and took payment in coins retained from their work. Local salaries helped determine local totals, including strings of 980 pieces in one district and 965 elsewhere. During the Qing dynasty, these workers also searched for older and rarer pieces that could be sold to collectors at higher prices. A tael of pure silver in sycee form traded for a fluctuating price of approximately 1000 cash.
The inscriptions on Chinese cash coins often named an emperor's era rather than specifying a denomination. Phrases such as tongbao, meaning "general currency," and zhongbao, meaning "heavy currency," accompanied those names. Qing pieces generally carried the emperor's era name and tongbao on the obverse, with the mint location on the reverse, most often in Manchu script. Their lettering could use seal, clerical, regular, running, or grass script, among other styles. The Tang dynasty's Kaiyuan Tongbao influenced inscriptions both within and beyond China. Related currencies included Japan's mon, Korea's mun, the Ryukyuan mon, and the Vietnamese van, extending the coinage pattern into neighboring monetary systems.
Production continued briefly after the fall of the Qing empire, including Minguo Tongbao pieces in 1912, before new Yuan-based coins displaced them. Trial pieces in the Hong Xian Tong Bao series are reported to have been minted in 1916 during Yuan Shikai's attempted monarchy, but did not circulate. Chinese cash coins remained in unofficial use in China until the mid-twentieth century. Vietnamese pieces continued to be cast into the early 1940s, while the last Chinese examples circulating in Indonesia remained in use in Bali until 1970. There, the coins also retained a place in Hindu rituals. Beyond monetary circulation, modern good-luck uses include hanging them on strings, around children's necks, and above sick people's beds.