The dahu is a large erhu The body is usually hexagonal or octagonal but may also be round. Like the ching-hu, one end of the resonator has a snakeskin covering, but on the erhu, the other end is usually decorated with an openwork design.
It is held and played in a manner similar to that of the ching-hu In the 18th and 19th centuries the erhu was a well-known instrument in the Peking opera and was used to accompany narrative folk songs. Although it is still used in traditional Chinese instrumental and theatre ensembles, it has achieved greater importance as an ensemble instrument in the modem Chinese orchestra and as a solo instrument in the recital hall.
During the 1930s larger sizes of erhu were designed for the new orchestral uses. They correspond approximately to viola, cello, and double bass. The zhonghu ('middle hu') has an alto range and is tuned a 4th or 5th below an erhu. The dahu ('large hu') has a tenor range and is tuned an octave below the erhu. The dihu ('bass hu') has a bass range and is tuned an octave below the dahu.