I'd appreciate it if you could help me
The takara mussel is a shellfish that lives in the sea. They have long been used as a symbol of safe childbirth because they resemble a woman's vagina when turned inside out, resemble the bulge of a pregnant woman's stomach, and are related to water, the source of life. In Japan, it is also called "Ko-yasu-gai" (childbirth shell), and it has been believed that holding it in one's hand at the time of childbirth will bring about a safe delivery. Shells have a long history of use as currency (money), as the Chinese character for "currency" in the word "coin" has the character for "shell. Shells are difficult to counterfeit, and their longevity and resistance to breakage make them suitable for use as money. The shell is particularly suited for use as money because of its uniform size and shape.
In the 18th century, Maldivian takara mussels were used as currency in exchange for slaves. European sailors purchased countless numbers of Maldivian cockles and traded them for human slaves in West Africa (the area in the lower left of the map above). Once the shells were paid, the slaves were loaded onto ships and sailed across the Atlantic, often to work on large plantations in the Caribbean.
European slave traders found it expedient to use shells in their dealings with African kings and merchants (ammunition, weapons, and other industrial products were also used in human exchange). The trade of importing shells at insignificant prices and exchanging them for slaves was highly profitable. At one time, as many as 150,000 cockles were exchanged for each slave.
In 1807, the British government banned the sale of slaves, thus ending the exchange of shellfish for slaves. Next, however, the takara mussels were used in exchange for coconut oil. At that time, most of the coconut oil used in the world was produced in West Africa. British traders continued to buy coconut oil from the Maldives' takara mussels. Coconut oil is closely related to the Industrial Revolution that took place during this period. It was used in large quantities as machine oil to make gears and other machinery run smoothly, as oil for lamps in homes and factories, and as an ingredient in detergents to clean factory dirt.
However, with the discovery of the takara mussel outside of the Maldives, its value dropped drastically as its distribution fees increased dramatically. （The more something is, the less it is worth.) Soon, a palm full of cockles was worth nothing. The exchange of cockles as money came to an end.
