Slave markets in Joseon period were based on human networks amongyangban families. Yangban families set up human networks to trade slaves andfarm fields and to deal with civil affairs and lawsuits. The network covered gunand hyeon regions in a small scale and the entire nation in a large scale. Members of the networks were local government officials and powerfulfamilies. Slaves of yangban families were distributed nationwide. The networksmade it possible to manage slaves. Important matters such as slave pricing were communicated by letters ofowners. Brokers were a head slave, suno (首奴) or hono (戶奴). They looked forbuyers and adjusted prices. They carried a credential document of owners, baeja(牌旨). Slaves were traded by documents without personal inspections. In thesense, the slave market was imaginary based on trust among yangban families. Transactions were guaranteed by the family reputation established for tens orhundreds of years. The characteristics of the human network were found in chingnyeom (稱念)letters. Chingnyeom means ‘Please understand my good intention’. Withchingnyeom letters, presents were exchanged. The presents ranged fromvarious agricultural and fishery products such as good quality paper, rice,barley, beans, dried pollack to monetary means such as cloth. Slave marketsexisted in the imaginary world of human networks and cemented by chingnyeom presents. The number of yangban family networks were tens andhundreds in the 16th century when slave system was most prevalent. Thedistribution was nationwide, as well. The network was combined with othernetworks of marriage, schools, and political parties. The networks playedimportant functions to maintain and expand yangban economy.