Gagok is also known as the Eternal Ring Jigok, which is a vocal piece that is included in the regular price along with sijo and lyric that were popular in the upper class society of the Joseon Dynasty. The lyric of Sijo is sung in the form of Chapter 5 to the orchestral accompaniment of Piri, Jeotdae, Gayageum, Geomungo, and Haegeum. Its artistic value is excellent compared to that of Sijo and its lyrics. Traditional songs are played by 16-night or 10-night Janggu Jangdan accompaniment, and are based on 24 songs and are divided into male, female, and male and female songs according to the classification of people.
The song originated in the early Joseon Dynasty, and the current song was formed at the end of the Joseon Dynasty. As the mandaeyeop and Jungdaeyeop gradually declined during the late Joseon Dynasty, the sagdaeyeop became more prevalent, and from the end of the 17th century, the sagdaeyeop became a variant of 1, 2, and 3. By the 18th century, Jungger, Pyeonggeo, and Duger were derived from the Great Lakes of Isu, and by the 20th century, they grew into huge vocal music like today's songs.
In 1988, Han Ja-yi was introduced to Wolha Kim Deok-soon, the owner of an important intangible cultural asset, Yeo Chang-ga-gok, and learned about the arts. Since 1992, he has been studying Namchang Song from Kim Gyeong-bae, the owner of Namchang Song, and from So Dong-gyu, Kim Gyu-yeol, and Park Gi-ok, the master singers of Naepoje Sijo, he learned how to make poems and sing lyrics. He won the gold medal at the 1992 national men's and women's sijo sang competition and the grand prize of the Jeonju Daesaseup Nori Sijo in 1993.