Party to high level decision making on the allied Ming-Joseon side and able to access all Joseon records, Yu Sŏngnyong's Jingbirok has become an invaluable source in the study of the conflict, and Chinese-Korean-Japanese relations.

Yu Sŏngnyong wrote the Jingbirok in order to prevent such an invasion from happening again, reflecting on the mistakes.

[2] In the preface he writes that during the conflict the Joseon state suffered "the loss of three capitals, and collapse everywhere" (三都失守，八方瓦解) reflecting on his own role in this he wrote that he was "not up to the task the nation entrusted, the ills that nation suffered was because of threats not grasped, this cannot be swept away, nor can death atone for this guilt" (無似受國重任，於流離板蕩之際，危不持，顛不扶，罪死無赦).

Yu placed the blame for the disaster suffered by Joseon on his own inadequate emphasis on national security, and was therefore resolved to properly document hard lessons dearly paid for, with the hope that following generations could avoid the mistakes that he had made.

The early form of the Jingbirok was completed by the time of the 37th year of King Seonjo's reign (1604) and consisted of sixteen scrolls and a coda: By 1633 (11th year of King Injo's reign) this had evolved into a widely read two volume format known as the Seoaejip consisting of the Jingibrok and Ryu Seong-ryong's The Anthology of Seoae (Korean: 서애집; Hanja: 西厓集)).