The structure of Biwang is the same as that of the Han Erhu, which is composed of the barrel, the rod, the peg, the jin, the horse, the strings and the bow.

There are no fixed specifications for the shape, and most of them are made by folk artists for their own use, with a total length of 55 cm to 68 cm.

piano
Cylindrical, there are three kinds of horn, wood or bamboo.

The horn tube is the earliest form of biwang, and it is mostly made of thicker bison horn, and the horn of the female bison is the best. Afterwards, because the bison horns were difficult to find, it was gradually changed to a wooden piano tube.

Wooden piano barrels are often made of walnut, birch, fir or pine, and a piece of log is hollowed out. . Bamboo qin barrels are made of old bamboo that has been naturally dried for many years, and the quantity is very small.

piano bar, peg
The cylindrical body above and below the rod is mostly made of hard wood. In Tibetan areas, it is often made of rhododendron wood, green oak wood or poplar wood produced locally. The headstock is mostly carved into a square tower or spherical shape, and two wooden pegs are placed horizontally on the right side of the piano bar. The shaft head is conical, and the shaft top is polygonal, irregular cylindrical or spherical.

Thousands of pounds
The middle and lower parts of the piano rod are cylindrical, and the top of which is fastened with silk strings, and the lower end of the piano rod is inserted into the square hole of the piano barrel.

piano, strings
There is a wooden bridge in the center of the leather surface of the piano. Zhang has two strings. Traditionally, black ponytail strings are used. In Sichuan Batang, black ponytails are used as the outer strings and white ponytails are used as the inner strings. In recent years, silk or steel strings have been used.

bow
Bamboo strips or twigs of the raspberry tree are used as bow rods, which are bent into a full bow or semi-circle. Both ends are tied with black ponytails as bow hairs. The length of the bow varies from 34 cm to 57 cm, depending on the player.