Cowrie Shell Money

Cowrie shell money refers to the use of the small, glossy shells of certain sea snails, chiefly the money cowrie (Monetaria moneta), as a means of payment and store of wealth. In China cowries were valued from at least the Shang dynasty in the second millennium BCE, and similar use is recorded across the Indian Ocean world, South Asia and West Africa, in some regions into the nineteenth century.

Cowries are often described as one of the oldest forms of money. They were durable, hard to counterfeit, roughly uniform in size and easy to count, which made them suitable as a unit of account as well as a portable object of value.

The money cowrie lives in the warm waters of the Indian Ocean and the western Pacific, not off the coast of northern China. Shells found at Shang sites must therefore have arrived through long-distance exchange, which made them scarce and prestigious in the Yellow River valley. Large numbers have been excavated from elite burials of the Shang period, including the tomb of Fu Hao at Anyang, which contained several thousand shells.

Inscriptions on Western Zhou bronze vessels record kings and nobles granting cowries to their followers, sometimes counted in strings. Whether cowries worked as general-purpose currency or mainly as prestige gifts and stores of wealth is debated among historians. Many scholars think they served several roles at once, being used in gifts, rewards and some exchange, without yet functioning as a fully fledged state money.

As demand outgrew supply, imitation cowries were made from bone, stone, shell and bronze. Bronze cowries mark an important step: they kept the familiar shape but were cast from metal, linking shell money to the later metal coinage of China. In the southern state of Chu during the Warring States period, small bronze cowrie-shaped pieces, often called "ant-nose money", became the main local coin, alongside the gold plaques that Chu also used.

In the north and centre other metal forms took over, including spade money, knife money and the round huanqian.

The clearest trace of cowries in China is in the written language. The character for cowrie, bei, forms part of many characters connected with value and trade, including those for wealth, goods, buying, selling, price and expensive. This is widely taken as evidence that cowries were closely associated with ideas of value in the period when the writing system was taking shape.

According to the Han historian Sima Qian, when the Qin dynasty unified China in 221 BCE it ended the monetary use of pearls, jade, tortoise shell, cowries, silver and tin, recognising only gold and its bronze ban liang coin. Cowries nevertheless remained in use far longer in the south-western region of Yunnan, which had direct links to the Indian Ocean trade, and were still used there in the Ming period.

Outside China, cowries were among the most widely used shell currencies in history. Shells harvested mainly in the Maldives were shipped to Bengal and other parts of South Asia, and later carried in great quantities by Arab and European merchants to West Africa, where they served as everyday money for centuries. The massive imports of the eighteenth and nineteenth centuries contributed to a fall in their value, a form of inflation driven by oversupply, and colonial authorities later replaced them with coins and paper money.

Cowries show how a commodity can become money when it is scarce, durable and widely accepted, solving the double coincidence of wants that limits barter. They also illustrate the limits of such money: when the supply of the commodity grows faster than trade, it loses its role as a reliable store of value.

• British Museum – Collection online
• American Numismatic Society