Hopae were identification tags carried by Koreans during the Joseon dynasty, recording the bearer's name, place of birth, status and residence.

[2] Certain military officials were required to wear hopae in 1391[3] (imitating a similar practice by the Yuan dynasty)[4] and its further implementation was continually raised by the Joseon government from 1398.

[1][3] The desire to control migration was cited as a major reason behind the system in the edict which established the hopae law.

[3] Over a period of 260 years, it was implemented for just 18,[3] and the Seongjong Annals reports that of the men with tags only 1-20% actually served in national military service.

[3] King Sejo revived the system in 1458, again with the aim of controlling the movement of people, this time in order to aid in suppressing the rebellion by Yi Jing-ok in Hamgil Province, which found widespread support among peasants who had fled from their homes; the law would remain in effect for twelve more years.