The primary Korean instrumental genre that bridges folk and art traditions is sanjo (on these releases romanised as ‘sanzo’). A performance of sanjo is given by a single melodic instrument accompanied by a drum – almost always the changgo, an hourglass-shaped, double-headed instrument. It starts with a non-metric section that establishes tonality, then progresses from a slow and intensely emotional chinyang (in 18/8 time) through an increasingly fast sequence of movements (in 12/8 and 4/4), each of which is based around a single, repeating rhythmic cycle (known as a changdan).

Sanjo originated as a style for the gayageum (12-stringed zither), an instrument dating back to the fifth century CE. SongJa Chee plays the school of sanjo devised by her mother – the famous Song Geungyeon – and it's a style that illustrates how a genre originally from the south-west of Korea reached the urban capital. Both of Chee's parents were sufficiently celebrated to be appointed Human Cultural Properties. A complete performance can be lengthy and here Chee plays non-stop for 72 minutes. The second disc features a much younger performer, JeongHyun Chu, who trained in the south-west. She plays a different sanjo school for the same zither, that of Ch'oe Oksam. Curiously, Chu is accompanied by the puk barrel drum, an instrument normally reserved for accompanying pansori, epic storytelling through song. From the beginning of the 20th century, versions of sanjo were introduced for virtually every instrument, and the third disc features Shu playing Korea's most strange instrument, the ajaeng (bowed zither). Shu gives two shorter sanjo performances in styles devised by his father and by his teacher. While the ajaeng appears in Chinese historical texts from a thousand years ago, where the rosined bow is said to make the instrument creak, only in Korea is it still used. Nasal, guttural, and unexpectedly delightful as the bow shifts suddenly from large to small movements and juxtaposes loud to soft, it is at once pleading then lyrical. The pentatonic sound world is almost jazz-like, as the tuning tends towards flattened Western pitching. Shu's album was recorded live, and concludes with an instrumental ensemble playing arrangements of folk songs.

All three albums are all exemplary performances, beautifully recorded in traditional wood and plaster Korean houses (hanok), to give an acoustic that seems to make low pitches resonate from the suspended floors while absorbing higher pitches in the walls. Accompanied by lavish booklets, the whole package would be perfect if only the liner notes were intelligible and sensibly romanised.