People say this song type is not Hyang-Ka, because it has no rule to Hyang-Ka. So thye call it just a 'song', for it is the only song ever founded before United 'Shin-Ra' Dynasty in not hyang-Ka type verval song.
'Jung-Eup-Sa' has been remained as verval song. In Korea Dynasty, It was translated as Chinese and got written. 400 years after, it was rewritten in Korean.
Some scholars say it has an original thing of 'Si-Jo' - the popular songtype in Cho-Sun Dynasty, for it can be devided as three parts when you get rid of the chorus line. (In the song listed, you can find it in 3th, 4th, 7th, 10th and 11th line.