13 Port, which means Guangzhou 13th Line, is a firm specializing in foreign trade in the Qing Dynasty, and a monopoly institution designated by the Qing government to specialize in foreign trade. 13 is the 13 Guangzhou bank, which specializes in foreign trade in Qing dynasty. The port is a monopoly institution designated by the Qing government to specialize in foreign trade. Port number. 13 refers to Guangzhou 13th bank, which was specialized in foreign trade in the Qing Dynasty, and was a monopoly institution designated by the Qing government to specialize in foreign trade. During the "one-stop trade" period, the thirteen banks reached their peak and became "Tianzi Nanku", which had direct trade relations with major countries in Asia, Europe and America.