The đoan instrument having four strings is of the chordophonic family of  plucking branch of Viet people and some ethnic minorities in the North of Vietnam. Similar with the đoan instrument, Hmong people have the tha chin instrument and Lo Lo people have the zen xin instrument with the thinner resonator, which is decorated with patterns and has resonating holes.

The resonator has the round shape. The surface and the bottom are made of thin wood and are covered tightly (no resonating). They have the diameter of about 35 cm. On the surface are eight bamboo frets (installed in accordance with the equal tempered heptatonic) and bridge for keeping strings. Its edge is made of wood about 7 cm high.

The neck is made of hard wood with the length of about 20 cm and two bamboo frets are installed on it. Strings are made of silk or nylon and tuned at the perfect fifth interval (Sol, Sol, Rê, Rê).

The tuning peg is made of hard wood (there are four pegs) going through four holes above the neck.

The plucking piece is made of plastic or tortoise shell.

The đoan instrument has the ambitus on two octaves.

The sound of the đoản instrument is pure, bright, and quite sharp.

Performance pose:  The player sits in the cross-legged way on the mat or sit on the high chair about 60 cm in height.

The đoan instrument is used in the octet orchestra or on the cai luong and tuong stages.

Right-hand technique:  The instrumentalist has to have long nails and uses the thumb and the index finger for plucking the instrument. At present, the most popular way is using the plucking piece.  

Plucking technique (ngón gảy): It means using the plucking piece to pluck strings downwards. Its symbol is the upside-down U. Plucking-up technique (ngón hất) means using the plucking piece to pluck strings upwards and its symbol is V character.  

Tremelo technique (ngon vê): It means using the plucking piece to pluck strings downwards and then upwards uninterruptedly, quickly, and steadily. Its symbol is three diagonal lines at the tail of the note. This tremolo technique produces resounding sounds from the beginning to the end of the vibration of the note, which makes the note more lively and rich in expressiveness. Therefore, it is regularly used.

Left-hand technique: tremolo (ngon vê), glissando (ngon vuot), pressing (ngon nhan), and trilling (ngon lay) and simultaneity. The đoan instrument has the ability of performing the melody quickly and very flexibly.

Pressing technique (ngon nhan): It means to create two succeeding sounds, which are played in ligature; therefore, the sounds are as soft as the voice with many intonations and many emotional expressions. To play this skill, the right finger plucks the instrument only once. The symbol of pressing technique is the arrow going around up or down, which is put from the note, which is pressed, to the next note.

Trilling technique (ngon lay): It can be called clapping finger (ngon vo). People use the first finger to press the fret and the right hand to pluck the instrument. When the sound is just produced, people use the second finger or both the second and third fingers to clap on the strings at the conjunct right under the neck. This new sound will be higher than the main sound a conjunct tone (the pentatonic scale). The sound of trilling technique is similar to the sobs expressing the agitating emotion.

Trilling technique (ngon lay ren): It means to perform trilling finger quickly and more with the co-ordination of the tremolo playing of the right hand. Its symbol is the abbreviation of Trille and two diagonal lines above or below the note (if the whole tone) or above the tail of the note.

Glissando technique (ngon vuot): It is using the left hand to make glissando on the string while the right hand does not perform plucking playing and tremolo playing. The sounds produced by glissando technique are soft and weak, but they cannot be in ensemble. As a result, sounds produced by glissando technique are often alternated with the sounds produced by plucking playing, and tremolo playing so that the sounds produced by glissando can inherit the echo of those sounds. The symbol of glissando finger is the dash between two notes.

Glissando with tremolo: Its symbols are the dash between two notes and two diagonal lines at the note with the tail. If the note without the tail, two diagonal lines are put above or below the note.  

Position of the đoan instrument in the orchestra

The đoan instrument is used in the octet, tuong, and cai luong orchestras