Gasa, which is part of the country’s traditional vocal music, refers to a long narrative in verse. Based on relevant records, it is presumed that this form of verse started to be written after the reign of King Yeongjo (r. 1724-1776).
A total of 12 pieces have been handed down and survive today. They are Baekgusa, Jukjisa, Hwanggyesa, Eobusa, Chunmyeongok, Sangsa Byeolgok, Gilgunak, Gwonjuga, Suyangsanga, Cheosaga, Yangyangga, and Maehwa Taryeong. It is not known who composed these songs or wrote their lyrics, but it is thought that the tradition of Gasa was established toward the end of the Korean Empire (1897 – 1910).
The narratives of Gasa are very long and are not regularly styled, and so it is not clear how singers are supposed to arrange their diverse features and sounds. Melodies differ slightly from narrative to narrative. Modulations and repetitions appear characteristically. As for their rhythm, Baekgusa and Jukjisa have dodeuri rhythm (sextuple time). Sangsa Byeolgok, Cheosaga, and Yangyangga have quintuple time. Gwonjuga has no fixed rhythm. Basically, Gasa is sung without instrumental accompaniment, but sometimes it is sung to the accompaniment of piri (flute), haegeum (two-stringed fiddle), daegeum (bamboo flute) or janggo (hourglass-shaped drums).
As a free-style song, Gasa is good at expressing people’s sentiment or natural beauty. It is a song sung by professionals, and is the country’s indigenous music featuring peacefulness and locality.