- Robert C. Provine
Double-headed hourglass drum, the chief percussion instrument of Korea (chang: ‘stick’; go: ‘drum’). It is also known as changgu (especially in central Korea and among folk performers), sŏlchanggo (for the instrument used in the farmers’ percussion band music nongak), and seyogo (a Chinese term used in certain historical sources, meaning ‘narrow-waisted drum’). The changgo body is made in various sizes, and in general a changgo used in court music and for subtle accompaniment will be larger and deeper-toned than one used in nongak and in certain types of folk song.
The body of the instrument is made of a single piece of paulownia wood, fashioned in the shape of an hourglass and hollow even at the narrow waist. The body ranges in length from roughly 40 to more than 60 cm and in diameter at the ends from roughly 20 to more than 30 cm. It may be painted red and decorated with traditional motifs, though some drums used in nongak are left with a natural finish. The circular heads of animal skin are mounted on metal hoops of larger diameter than the ends of the wooden body and overhang by about 6 to 8 cm. The two heads are laced directly to each other by cords running from hooks attached to the metal hoops. Small leather sleeves placed on pairs of adjacent lacing cords can be manipulated to vary the head tension; the drum is tuned to an effective resonance, but not to any particular pitch. According to the Akhak kwebŏm (1493) both heads were originally of horse skin, thick on the left and thin on the right; the left skin is now usually of cowhide and the right of dog skin or sheepskin, except in the case of the medium-sized sŏlchanggo used in nongak, which has dog skin for both heads.
In most types of Korean music the changgo is placed horizontally on the floor in front of the seated performer. The left face is struck with the open left hand, the right face with a slender stick of bamboo; the right face can be struck in the centre in loud music, or along the protruding flange (producing a crisp, high-pitched sound). The open hand produces a deep, resonant sound, the stick a drier, penetrating sound. In the case of nongak, which is performed outdoors and requires considerable volume of sound, the changgo is strapped with sashes onto the performer, who holds a bamboo mallet (with a ball of wood or plastic at the striking end) in the left hand, hitting either the left or right heads, and a sturdy bamboo stick in the right hand, striking the centre of the right skin in a virtuoso technique, full of visual display. Dancers sometimes play it strapped to their waist while dancing.
The hourglass drum in Korea can be traced back to mural paintings of the Koguryŏ period (37 bce–668 ce) and artefacts such as stone and metal reliefs of the Silla period (57 bce–935 ce). The name changgo appears in literary references from the year 1076, and both the instrument and the name have remained essential to the tradition ever since: virtually all surviving forms of Korean musical notation (tablature, letter, graphic, etc.) include parts for the changgo, and it is the one instrument vital for nearly every performing ensemble.
At present the changgo is found in most genres of traditional Korean music, whether court, aristocratic, or folk. Normally its purpose is to articulate the repetitions of structural rhythmic patterns as an accompaniment to melody instruments, but there is also a solo repertory of considerable rhythmic subtlety in nongak and the more recent small percussion ensemble samullori.
Related hourglass drums include the Korean kalgo, the several Japanese tzuzumi, and the Chinese zhanggu.
- Sŏng Hyŏn, ed.: Akhak kwebŏm [Guide to the study of music] (Seoul, 1493/R), 7.3b–4a
- Hayashi Kenzō: Dongya yueqi kao [Study of East Asian musical instruments] (Beijing, 1962), 106–23
- Chang Sahun: Han’guk akki taegwan [Korean musical instruments] (Seoul, 1969), 128–30
- K. Howard: Korean Musical Instruments: a Practical Guide (Seoul, 1988/R), 118–62