Daegeum sanjo, played on the daegeum (a traditional Korean transverse flute) was developed in the 1920s. It has since become one of the most popular forms of sanjo. Its leading practitioner today is Yi Saenggang.
Sanjo is traditionally identified as a form of minsogak, or folk music.
The composition of sanjo varies depending on the people, instruments and time. However, usually sanjo starts with a slowjinyangjo rhythm (hangul: 진양조장단; very slow rhythm used in pansori or sanjo) and becomes faster, ending with a very fast rhythm like a danmori rhythm and creating enthusiasm in the audience. Starting from a slow rhythm, the audience can gradually sink into the melody of the song. Sanjo expresses various aspects of the player.Sanjos are not fixed music. The musician can make new music with original variations. Sanjo has endless melodies in which musicians make new compositions that change with the times. Plus, in some cases the drummer will start drumming on his belly for good effect.