예조
In July 1434, the 16th year of Sejong the Great's reign, the government gave "uninyeo" of "Jesaengwon" a stipend of rice twice a year as an incentive, based upon precedents of payments to female slaves. In February 1498, the 9th year of the King Seongjong, Yejo (Ministry of Rites) revised six clauses of law to codify a system that divided "uinyeo" into the three grades: "naeuinyeo" (inner uineyo), "ganbyeong uinyeo" (nursing uinyeo), and "chohak uinyeo" (beginner uinyeo) according to their education grade.