The dan bau is a unique traditional Vietnamese string instrument, easily recognized by its enchanting and melancholic sound. Often referred to in English as the "Vietnamese monochord" or "one-string zither," the dan bau consists of a slender wooden sound box with a single string stretched across it. One end of the instrument features a flexible rod or handle made of bamboo or rattan, used to adjust the string's tension and create pitch variations. The musician plucks the string with a pick, while the other hand manipulates the rod, bending it to shape delicate glissandos and expressive tonal changes. This method allows the dan bau to produce a surprising range of pitches, harmonics, and emotional nuances, making it a powerful tool for storytelling and musical expression.

The dan bau holds a special place in Vietnamese culture, appearing in both traditional and modern contexts. In ancient times, it accompanied recitations of poetry and folk tales, providing an evocative backdrop that heightened the emotional impact of the narrative. Today, the instrument is used in solo performances and traditional orchestras, as well as in contemporary fusion music that blends Eastern and Western influences. Its voice is often described as hauntingly beautiful—capable of mimicking the human voice, expressing joy, sorrow, and longing with subtle inflections unique to Vietnamese musical idioms. For many, the dan bau is more than an instrument; it is a symbol of the soul and identity of the Vietnamese people.