Clients (yinke 蔭客) were nominal members of the households of wealthy and influential families, some were relatives, but others were not related to the family of the patron, yet others were peasants and craftsmen. The use of keeping clients was widespread during the Jin 晉 (265-420) and Southern and Northern Dynasties 南北朝 (300~600) periods.
Laws regulated that the patron was allowed a certain number of clients which were not taxed. The number depended on the official rank. Families of ranks 1 and 2 were allowed to protect 15 tax-exempted client households (yinhu 蔭戶, baoyinhu 苞蔭戶, nihu 匿戶), such of rank 3, ten households, eminent families of rank 4, seven households, of rank 5, five households, of rank 6, three households, of rank 7, two households, and eminent families of ranks 8 and 9, could nourish one client household.
This rule from the Western Jin period 西晉 (265-316) was changed by the Eastern Jin 東晉 (317-420), so that eminent families were allowed to protect even more client households. In practice, these numbers were usually widely surpassed, with the consequence that the word yin 蔭 "protection" obtained the meaning of yin 隱 "hidden, obscure, illegal" (hence also the term yinhu 隱戶).
Client households normally served their patrons in many different fields. They were advisors, retainers, servants, soldiers or peasants. Instead of paying taxes and delivering corvée labour (yaoyi 徭役) to the government ("the public"), client farmers paid a rent or services to their patrons.
Many client households came into being when peasant refugees (liumin 流民) sought shelter in the service of a powerful local family as "refugee households" (fuke 浮客, taohu 逃戶), and gave up their independence for economic security.
The custom of keeping client households vanished during the Northern Dynasties period 北朝 (386~581), when the tax system was changed (see equal-field system) to a household tax system which did not discern between the status.
Emperor Wen 隋文帝 (r. 581-604) of the Sui dynasty 隋 (581-618) officially abolished the client household system (yinke zhi 蔭客制). After that time, client households were mainly restricted to that of peasants which – out of different reasons – gave up the ownership of their fields and became client-farmers (dianke 佃客, diannong 佃農).