It is not common knowledge that the current erhu used in the Chinese orchestra is a modified instrument.  Few know that the instrument was modified after the revolution by a gathering of musicologists, performers, enthusiasts, teachers and students to increase the potential of the erhu.  The unmodified erhu was considered defective in many ways.  Notes between octaves were inconsistent in terms of volume.  Its range was extremely small, and lacked the clarity found in most other instruments.

Through the process of reformation, other forms of huqin were created or modified to fill the gaps of sound that were missing in the developing Chinese orchestra.  The new huqin developed or reformed include the gaohu, erhu, zhonghu, dahu and dihu among others.

The gaohu, before its reformation, was also known as a yuehu (Cantonese huqin) or nanhu (southern huqin).

The gaohu is often considered the higher-pitched version of the erhu and is commonly associated with Cantonese music.  Smaller than the erhu, the gaohu is sometimes played between the legs. Its invention is largely credited to the Cantonese musician Lu Wencheng, who modified the gaohu based on the erhu.

Reaching higher pitches than the erhu, the instrument sounds brighter and more piercing.  The same techniques used on the erhu can be employed on the gaohu.  Usually, the instrument assumes the higher-pitched parts in the bowed stringed section of the Chinese orchestra, and takes over pitches that the erhu will have difficulty with or cannot reach.

With its sweet and delicate tone, the gaohu is often in the soprano voice of the bowed strings section of the modern Chinese orchestra. Apart from being the leader in Cantonese music, the gaohu is also used in folk ensembles and as accompaniments.

The most renowned repertoire for the gaohu is arguably Liang Zhu (The Butterfly Lover’s Concerto).