In the musical performance rule of ErHu, how to use bow and finger of left hand is analyzed, that is based on the moment balance principle and bowstring principle.
3
换句话说,二胡的弓不能从弦中离开,除非这两根弦中有一根卸下或断了。
In another word, one cannot take off the bow from the instrument unless one of the two strings is taken off or broken.