These six books are collections of 300 letters that King Jeongjo (r. 1776-1800) wrote and sent to Sim Hwan-ji (1730-1802), a powerful official who served in various high-ranking posts of the Joseon government, between 1796 and 1800. As the letters generally concern state affairs, they are primary sources for understanding the political situation of the Joseon dynasty during the late eighteenth century.
The letters show that the king used paper of varying quality ranging from the highest quality ""letter paper"" and ""moss paper"" to the rather rough ""bark paper"". They were also written in various registers and formats, and thus constitute an interesting source material for the study of letter writing in the Joseon period (1392-1910).