Sanjo is characteristic of music of the southern region. It is an instrumental version of Pansori, a dramatic song of the southern region.
The instrumental version of dramatic song is strongly emotional with the conspicuous alternation of tension and relaxation.
The instrumental also music is cast into three movements. The first slow movement (Jinyangjo) mostly consists of phrases of four measures, each measure equivalent to six half notes. The second movement (Jungmori) mostly has four-measure phrases of triple time. the third fast movement (Jajinmori) has mostly two-measure pfrases in 12/8 time, ending with the faster movement (Danmori) in 4/4 time which is very rare in Korean music. Within this framework the soloist freely expresses the various emotional content.
The slow movement where the long melody undulates with micro tonal shading, opens with the melody in the so-called u mode which gives the effect of stateliness and ends with the melody in the Gyemyeon mode which is sorrowful. The moderate movement is enlivened by music in the light Gangsan style. In the fast exciting movement the twelve-stringed zither, Gayageum, weaves complex rhythm such as hemiola and other devices, while the hourglass drum keeps the fundamental rhythmic pattern. Hence the inter-locked rhythm is comparable to the dissonance in arousing mental disturbance. Because of its emotional content and virtuosity, Sanjo is today most widely appreciated.