Dan Doan is a shortened version of the Dan Nguyet and is a two-stringed lute with a flat, circular sound
box which is shaped like a moon.
This instrument has an appearance similar to those of other East Asian Moon shaped lutes, the Yue qin of China, the Wul Kim of Korea, and the Gekkin of Japan. However the Vietnamese Dan Doan can easily be distinguished from others by its short neck, the prominently raised fret, and the performance practice. This is an important plucked stringed instrument used in so many kinds of musical or theatrical performances such as solo, song accompaniment, instrumental ensemble, chamber music, ritual music,royal court music...and this instrument (Dan Nguyt) was placed on the first position of the five perfect instrument (Nhu tuyet: Tranh, Ty, Nhi, Nguyet, Sao) in chamber music.
In chamber music of the South Vietnam , the musiciam who plays this instrument also conducts the ensemble by keeping the Song Loan ( the percussion instrument which looks like castanets, is used to keep the beat for the song playing), the Dan Nguyet Dan Doan has been widely appreciated by the Vietnamese for centuries.
The Dan Doan ,and Dan Sen are copies of the Dan Nguyet in smaller shapes.
The Dan Doan has a round thin sound box with a short neck and two strings while the Dan Sen has a flower shaped sound box with two strings on its neck which is longer than those of the Dan Doan.
In addition to the different shapes compared to the Dan Nguyet, the frets of the Dan Doan or the Dan Sen are fixed in diatonic scale instead of pentatonic scale of the Dan Nguyet