Where is the most authoritative certificate for dulcimer grading?

Central Conservatory of Music, China Conservatory of Music, Sichuan Conservatory of Music, Tianjin Conservatory of Music, etc.

There are many musical instrument grading institutions, but the mainstream is definitely the grading of major conservatories. Among them, Central Conservatory of Music, China Conservatory of Music, Sichuan Conservatory of Music, Tianjin Conservatory of Music and so on are all famous. There is a message that many parents and even many musical instrument training institutions are not clear about. Friends who want to see this answer should pay attention to the fact that children's grading information needs to be on official website to be the most authoritative!