With correct Vietnamese accent marks:
In Hanoi I found a music store and purchased a Dàn Bâù, also known as the dan doc huyen (single-string instrument). It is a real unique instrument with a wammy bar and a jack for amplification.
LINKS TO SOUND AND VIDEO CLIPS BELOW
In the years since then (1998) I did a little research. The word bau means gourd and refers to the dried gourd fastened to the handle, surrounding the string at the point where is connects to the handle. In the past this gourd may have served as a resonator, but today it survives as a decorative feature. Nowadays the dan bau is constructed using hardwood for a frame and softwood for the surface. The handle is made of flexible carved bamboo or water buffalo horn, and the string is made of metal.
Traditionally the dan bau has played in the groups of blind musicians, in Vietnamese chamber music (nhac tai tu). More recently it also takes part in the ensembles of cheo and cai luong theatrical music. In Vietnam today there is a growing virtuosic literature with solo works and concertos for the dan bau. The earlier dan bau xam is constructed from a split bamboo tube. It used a silk string and occasionally substitutes a half coconut shell for the dried gourd (Bau). In the days before amplification a trunk could be placed under the instrument as a resonator.
Historical records trace the invention of the dan bau to 1770. but some scholars have claimed earlier origins and antecedents for the instrument. Some speculate that it originates from a string stretched from the teeth, others believe its antecedent is the trong quan -- a "drum" consisting of a rope fastened to the ground at both ends stretched over pole that serves a bridge. This pole is positioned over a trunk, or empty pit that serves as a resonator. Ta Tham believes it originates from the tan mang, an instrument of the Muong minority constructed from a bamboo tube with a bamboo thread carved from out of it that is plucked like a string.
None of these instruments, however, employ harmonics, the performance technique that makes the dan bau unique. Although it only has one string, it can emit all the sounds in the pentatonic scale. The eight notes in Vietnamese music give modulations of greater amplitudes than those obtained by any other single-stringed instrument in the world. It uses these harmonics exclusively, produced at nodes at 1/2, 1/3, l/4, 1/5 and 1/6 the length of the string.
A small bamboo plectrum held in the right hand plucks the string while the lower side of the hand stops the string at the appropriate node. The left hand moves the handle to bend the pitch downward by moving in the direction of the instrument, or upward by pushing the handle away from the instrument. The pitch can bend as much as a 4th or 5th in either direction. The left hand also produces a variety of vibratos, glissandos and grace notes. The instrument's virtuosity and expressiveness are to found in its left hand technique, which should have a subtlety that mimics the sound of the Vietnamese singing voice or declaimed poetry.
More about Viet music from Viettouch.
If you don't have Quicktime, try this windows movie file that should play in Media Player.
If the link doesn't play, right-click and save target (note where you download it) and then try playing the audio or video).
Word of the day:
A rapid slide through a series of consecutive tones in a scale-like passage
(I'm working on this and still learning... please let me know what works (or doesn't).
On my deck, bending a note, in an
embroidered Vietnamese T-shirt.