found: Grove music online, viewed August 28, 2014:under Korea 3, Folk music (A more recent (late 19th-century) virtuoso instrumental form, partly derived from p'ansori, is sanjo, played on a single melody instrument (which may be any of a number of standard Korean string or wind instruments) with Changgo drum accompaniment. Unlike p'ansori, in which rhythmic patterns vary according to the emotional content of the story, sanjo presents four or more rhythmic patterns in ascending order of metrical speed, each movement being set to one rhythmic pattern and the slow movements being more intensely ornamented in melody.)