《Nanjung Ilgi》 is the dairy that Chungmugong Yi Sun-sin recorded for the affairs of 7 years that began from the year that the Imjin War broke out to the time of his death at Noryang Battle (1592. 1. 1~1598. 11. 17).
Originally, Yi Sun-sin did not have any special name for his diary. The name of 《Nanjung Ilgi》 was attached after Yi Sun-sin passed away in 1798 (the 19th year of King Jeongjo) with the publication of 《Entire Collection on Chungmugong》 with the convenience of the editor.
There are two sets of 《Nanjung Ilgi》 known to this present time. One is the initial copy that was recorded by the personal hand-writing during the headquarter with 7 books and 205 sheets and it had been designated as No. 76 of the National Treasure and it is kept in Hyeonchungsa, Asan. Another is on 《Entire Collection on Chungmugong》 with four volumes (Volume 5~7).
《Entire Collection on Chungmugong》was the records that Yoon Haeng-im, a literary official of Gyujanggak, and Yoo Deuk-gong of inspection officer of Yeomungwan who had the order of King Jeongjo fathered in three years of research, and it is consisted of a total of 14 volumes with his poetry, janggye, Nanjung Ilgi, miscellaneous magazines and other data.
Contents of 《Nanjung Ilgi》 have slight difference between the initial copy and later copy. The editors of the previous publication had the contents of deleting in the process of copying the hand-writing of Chungmugong that the contents of the initial copy is not consistent on the full copy version. On the other hand, the later edition of the 《Nanjung Ilgi》 has some parts for more record than the initial copy.
The initial copy of 《Nanjung Ilgi》 omitted the record ranging from January 1 to April 30, and the record of October 8 through 12 had its record smaller with less number of original record than the entire volume of addition. This is indicative of having some original writing of the diary removed at the time of editing for the 《Entire Collection on Chungmugong》.