Erhu vibrato before Western contact?

Question

Was vibrato known as a technique in China before the introduction of Western string instruments? How common was it to use vibrato when performing the erhu?

Answer 1

Vibrato on an instrument evolved naturally as a way to embrace the characteristics of the human voice to create a sound that expresses human emotion and spirit. It's always been present in instrumental music except in some styles that intentionally omitted it in order to make a purer sounds. However, there has been much controversy about its use and origins. Some instruments, of course, are easier to make a vibrato and modern string instruments make vibrato more easily than the viol da gambas did. Also, in the Romantic period which focussed on passion and emotion, vibrato became more frequently used. It is now almost universally used in orchestral instruments unless it is specifically omitted by instructions in the score. This is one of the factors that makes the sound of modern orchestras so rich.

As you mention, the erhu is a particularly "vocal" instrument both with vibrato and the glissandos between notes. It is, in my opinion, among the most soulful instruments because it emulates the human voice so well.