What string is used to play the notation of erhu on the grassland?

Watch the notation of Erhu on the two-stringed grassland.

Erhu has two strings, one is the inner string and the other is the outer string.

Erhu is a traditional stringed instrument in China, with two strings. It began in the Tang Dynasty and has a history of 1000 years. Erhu consists of a body, a string system and a bow.