How it began
The dan bau is a one-string zither native to Vietnam, and its origin is obscure. The earliest written records date to 1770, though scholars estimate it is up to a thousand years older. The Garland Encyclopedia of World Music, quoted by the Vancouver Inter-Cultural Orchestra, says it was an instrument of choice at the Tran imperial court of 1225 to 1400 and also an instrument of blind street beggars. A legend tells of a blind woman who played it in the market while her husband was at war. Some scholars relate it to the Thai pin pia, while others hold that it is uniquely Vietnamese.
Before it existed
Earlier forms were made from plant materials. Wikipedia describes the original as a tube zither built from a bamboo tube, a wooden rod, half a coconut shell and a silk string, and the Vancouver Inter-Cultural Orchestra notes that the body was once a long dried gourd and the stem was bamboo. Modern instruments use a wooden soundboard, a stem of water buffalo horn, an electric guitar string and a tuning machine.
How it works
The instrument has a long, narrow sound box with a tall flexible stem at one end. A single string runs from the box to a small gourd-shaped resonator on the stem. The player touches the string lightly with the edge of the hand at a nodal point while plucking, which sounds a harmonic instead of the open string. The other hand bends the stem to raise or lower the pitch and add vibrato, so one pluck can carry a whole melodic phrase. The nodes used are those of harmonics 2, 3, 4, 5, 6 and 8.
How it spread
The instrument is also played by the Jing people of China, who call it the duxianqin, and by the Muong people. The sound box is narrow and the instrument is quiet, so it was traditionally played in intimate settings. With the magnetic pickup it moved into ensembles, large concerts and popular music, and a bass version with a very thick string was adapted from it.
Where it stands today
The dan bau is played solo and to accompany folk songs, tales and poetry in Vietnam. Electric versions with a small amplifier are now usual in ensemble playing. A set of small movable frets placed under the string at nodal points, credited to the master musician Chi Khac, is a recent addition.
