What is "shuangyu"

Shuangyu was a port on Liuheng Island off the coast of Zhejiang, China. During the 16th century, the port served as an illegal entrepôt of international trade, attracting traders from Japan, Southeast Asia, and Portugal in a time when private overseas trade was banned by China's ruling Ming dynasty. Portuguese sources called the place Liampó, taking the name of the nearby city of Ningbo on the mainland. Shuangyu's days as a smuggling hub and pirate haven began as early as 1524 and lasted until its destruction by the Ming navy in 1548, an event that was greatly exaggerated (and wrongly dated) by the 16th-century Portuguese travel writer Fernão Mendes Pinto.