In early China, slaves were an important component of society. They belonged to a master (a private person or the state), for whom they worked. The most general term for slaves is nuli 奴隸, while the expression nu-bi 奴婢, introduced during the Han period 漢 (206 BCE-220 CE), discerns between male, and female slaves, respectively. The same is true for the pre-imperial term chen-qie 臣妾, chen referring to male (renchen 人臣), and qie (renqie 人妾) to female slaves (note that the word chen 臣 also means "state functionary", and qie 妾 "secondary wife" or "concubine"). The words chen and qie were therefore also used as first-person pronouns meaning "your servant, me". Other general terms for slaves are – changing over the ages – rennu 人奴, rennuqie 人奴妾, lu 虜, lu'er 盧兒, pu 僕 (仆), zanghuo 臧獲, cangtou 蒼頭, tong 僮 (or 童, meaning "child", "young slave"), jiaren 家人, shu 豎 or xi 奚 (female).
The total number of slaves during the Han period can be estimated to 2-3 million persons, of which about ten per cent were owned by the government (Ning Ke 1991: 794).
Slavery is the result of several different factors, all of which based on the acquisition of human labour that could be controlled in all aspects. The Shang 商 (17th-11th cent. BCE) and Western Zhou 西周 (11th cent.-770 BCE) dynasties used to produce slaves by conquest, as war captives (modern term fulu 俘虜) obtained from military campaigns against other states (fangguo 方國) or free tribes. Shang-period terms for war-captive slaves were Qiang 羌 and Yi 夷, both terms later referring to non-Chinese tribes or "barbarians". Some of the war captives were used as human victims for sacrificial offerings (see renxun 人殉), while others were made state-owned slaves (guannu 官奴). The custom of making war captives human victims disappeared during the Western Zhou period. The inscription of the tripod Xiao Yu ding 小盂鼎 from reports of 3,800 skulls of killed enemies and 3,810 war captives (Qiu 1992: 741). The custom of abducting the young people of a defeated enemy to use them as farming slaves (yong 庸) is still mentioned in the Warring States-period 戰國 (5th cent.-221 BCE) book Weiliaozi 尉繚子 (ch. Wuyi 武議), but enslavement of war captives gradually decreased in importance, even if the use of enforced selling (lüemai 略賣) is attested for the Han period. At the same time, war-captive slaves were more and more privatized and became property of individual families.
Another source for slavery was penal enslavement (zuili 罪隸), a punishment making an offender and his family state-owned slaves. In 179 BCE, Emperor Wen 漢文帝 (r. 180-157 BCE) abolished collective liability, but it was re-introduced soon. Males usually served with hard labour for government offices, while females pounded grain (chongmi 舂米). This kind of punishment was much more liberal than the five corporal punishments used during the Warring States period, but penal labour (tu 徒) might be imposed in addition to penal tattooing (jing 黥). The legal statues of the state of Qin had a distinct vocabulary, as can be seen in the bamboo slips unearthed in Shuihudi 睡虎地 close to Yunmeng 雲夢, Hubei. Penal slaves served for three years in the construction and crafts labour (guixin 鬼薪 "gathering firewood for the spirits"), the sifting of white sacrificial grain (baican 白粲, female counterpart) or the construction of city walls for four years (chengdan 城旦). Some of these punishments were limited in time which makes this type of slavery only temporary. Moreover, members of the nobility were allowed to live in their own houses.
In times of hardship, family heads might sell their wives and children into slavery, or offer themselves on market. Yet this might also be a kind of temporary slavery, if the enslaved person only served as a hostage or security (zhizi 贅子) for outstanding payment. In early imperial times, the children of slaves (nu chan zi 奴產子) were automatically given the status of slaves.
Being the property of masters, slaves might be presented as a gift to someone else. This often happened among the nobility of the regional states of the Eastern Zhou period 東周 (770-221 BCE), or among states, as happened in 589, when the state of Lu 魯 offered the state of Chu 楚 a hundred each of carpenters, needlewomen and weavers to leave the territory of Lu. The law code Falü dawen 法律答問 of Qin speaks of slave maids (ying 媵) accompanying a bride to her new place in the groom's household. The tripod Hu ding 曶鼎 from the Western Zhou period gives evidence how five slaves were bought back by their former master. The public sales of slaves "on the streets" (shou yu lüxiang 售于閭巷) is attested for the late Spring and Autumn period (Zhanguoce 戰國策, Qince 秦策 1: 57). Before attacking the state of Wu 吳, King Gou Jian 越王勾踐 (r. 495- 465) of Yue 越 announced that the wives and children of soldiers refusing to obey command would be sold on the market. A similar punishment for military disobedience in mentioned in the Qin law canon Fengzhenshi 封診式. In case there were not sufficient government-owned slaves, the authorities might buy slaves from private owners. Sales and purchase of slaves was of course also common among private owners.
Seen from the Qin laws, private ownership of slaves was not restricted to the upper class. The price for a slave was during the Han period about 1-20,000 cash, which corresponded to 1-2 mu 畝 of fertile land (Ning Ke 1991: 794). Private owners might sell their slaves to the state in exchange for redemption from punishment (shuzui 贖罪), an official rank (jueji 爵級) or a government post.
Apart from temporary slavery, the status of slaves usually remained unchanged and was even inherited to children. The escape of slaves is often mentioned in Shang-period oracle inscriptions, and is also mentioned in the Classics Shangshu 尚書 and Zuozhuan 左傳, the book Mozi 墨子, and the divinatory book Rishu 日書, which is part of the bamboo texts from Shuihudi. Large-scale hunting for escaped slaves (you wang huang yue 有亡荒閱) might have been known during the very early Zhou period, as explained in the history book Zuozhuan (ch. Zhaogong 昭公 7). The book Lüshi chunqiu 呂氏春秋 (ch. Chawei 察微) mentions that the state of Lu was willing to buy free persons enslaved in another regional state. The Qin code allows to buy someone free from enslavement by giving up official rank or by substituting the person by one or two able-bodied (dinglin 丁粼) others, a price depending on the stamina of the slave. The Qin state also accepted replacement for female slaves if the replacement person served for five years in a border garrison (shubian 戍邊).
Another possibility for liberation were merits. A government-owned slave named Fei Bao 斐豹 in the state of Jin 晉 once killed Du Rong 督戎, a bullboy of Luan Ying 欒盈 (d. 550), who threatened the ducal sovereignty of Jin. He was rewarded by allowing him to burn his slave register (danshu 丹書). The nobleman Zhao Jianzi 趙簡子 (d. 475) of Jin also promised his slaves to liberate them if they beat his enemies. The Qin code Junjue lu 軍爵律 likewise promised liberty for slaves having killed an enemy and presented his head. On certain occasions, a state might proclaim an amnesty for penal slaves. Emperor Gaozu 漢高祖 (r. 206-195 BCE) proclaimed in 202 BCE an amnesty for people having themselves sold into slavery because they had been nearly starving. In 160, Emperor Wen freed all government slaves, and Emperor Wu 漢武帝 (r. 141-87 BCE) did the same when the rebellion of the Seven Princes had been put down. Several amnesties and liberations were pronounced by the emperors Guangwu 漢光武帝 (r. 25-57 CE) and An 漢安帝 (r. 106-125 CE).
State-owned slaves normally worked in agriculture or the industry. Males used to till and plough the fields, while women were occupied – just as free peasants – with the raising of mulberry trees and silkworms. Children used to guard the flocks and herds (herdsmen were called chu 芻, mu 牧 or mutong 牧童). If working in the industries, males were used in construction work (called gong lichen 工隸臣), while females pounded grain or produces wine. In the Warring States period, private slaves were also employed in the productive activities of rural households. Slaves might also be used as drivers (puyu 僕御). During the Shang period, they were even buried along the vehicles if their master had passed away. The ritual Classic Zhouli 周禮 (part Qiuguan 秋官) explains that slaves of foreign tribes (Manli 蠻隸, Minli 閩隸, Yili 夷隸, Moli 貉隸) were used as guardsmen.
Government slaves might even perform official duties (lao lichen 牢隸臣), sometimes even in their own profession, like scribe (nai shili 耐史隸; nai 耐 means "shaved head") or diviner (nai buli 耐卜隸). The history book Shiji 史記 (129 Huozhi liezhuan 貨殖列傳) even mentions a slave called Bai Gui 白圭 who was a formidable entrepreneur. Other types of slaves were used as servants in private households. They were called bi 婢, qie 妾, tong 僮, shu 豎, chen 臣, pu 仆 (often being castrates, yanren 閹人), zai 宰 (as cooks) or hun 閽 (as door-guards, often punished with cutting off a foot). Other slaves served as dancers or musicians. Rich persons might possess huge numbers of slaves, like Lü Buwei 呂不韋 (d. 253 BCE), merchant and eventual chief counsellor of Qin, owned as much as 10,000 slaves. In such large numbers, slaves apparently served according to strict division of labour.
Even if slaves did not have the rights of commoners, the advancement of legal structures in the Han period protected them somewhat from arbitrary cruelty and gave them the right to notify attempted homicide. In the early Han period, slave owners still had the right to request that a slave might be killed for a certain misdoing (ye sha 謁殺), yet from the reign of Emperor Wu on, several cases are known in which slave owners were punished for killing slaves unauthorizedly (shan sha 擅殺). Dong Zhongshu 董仲舒 (179-104 BCE) advocated more rights for slaves in this respect. Gong Yu 貢禹 (124-44 BCE) argued that high numbers of government-owned slaves without proper work would better be transformed into tax-paying commoners. The usurper Wang Mang 王莽 (r. 8-23 CE) condemned the arbitrary killing of slaves. Emperor Guangwu confirmed this thought by making no distinction between killing a slave and a commoner. A tax law of the early Former Han period 前漢 (206 BCE-8 CE) imposed a double poll tax on slave owners. Emperor Ai 漢哀帝 (r. 7-1 BCE) planned to restrict the number of private slaves per person. A law was abolished stipulating to punish a slave with public execution and presentation of the head (qishi lü 棄市律) for having injured a commoner. Finally, a law narrowed the frame of private selling of slaves.
Slavery was never publicly abolished, but remained a substantial part of the social system throughout the Southern and Northern Dynasties 南北朝 (300~600) and the Tang period 唐 (618-907). The boundary between slaves and serfs during that time was not always clear. More on that issue can be found in the articles client-farmers, tenant farmers and private armies.
War captivity was a common phenomenon in the turbulent times between 200 and 600 CE. Various regimes arrested peasants and brought them to their own territory to build up the economy and supply the capital. These persons must be seen as slaves, too.
The Northern Wei dynasty 北魏 (386-534), for instance, annihilated in 439 the state of Northern Liang 北涼 (398-439/460), and transferred thousands of farmers to their capital Pingcheng 平城 (today's Datong 大同, Shanxi). They were registered as "dependent households" from Liangzhou (Liangzhou lihu 涼州隸戶). The male members normally worked as farmers, but might also be drafted into the army of Northern Wei, or laboured in government-owned workshops. They were not entered in the tax registers and did not pay taxes. Their status as government slaves was hereditary and did not allow them to marry commoners. From the reign of Emperor Xiaowen 北魏孝文帝 (r. 471-499) on, they were allowed to dedicate part of their time for private production. This step transformed them from slaves to serfs. These families were only liberated in 577 and became "miscellaneous households" (zahu 雜戶).