Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
The bass gehu (低音革胡; pinyin: dīyīngéhú, pronounced [tíín kɤ̌ xǔ]; also called digehu or beigehu 倍革胡, literally "bass gehu") is a Chinese bowedstring instrument in the huqin family. It was developed by Yang Yusen along with the gehu in the 20th century. It has four strings and is the Chinese equivalent of the double bass.