The port of Haiphong in Tonkin had been declared a French concession and opened to foreign commerce for only a few years in 1880 when the harbormaster boarded the English ship Conquest. Hidden on the steamer he found eighteen children aged five to thirteen, all but one of them girls. Some were rolled in blankets, while others were in closed baskets covered in clothes. The harbormaster's find was one of the earliest documented accounts of a clandestine traffic within Asia across the China Sea, although the trade can be traced for centuries. It was a phenomenon that French commentators referred to as "LaTraite des Jaunes" to distinguish the Asian trade in slaves from the African trade.