How many people sing harmony parts in the songs of Japanese music master Himekami?

Part of the songs use an ancient language [Jomon language],

and many songs use folk songs and dialects from all over Japan.

There are very few ethnic groups in Japan, and the Ainu of the north are present in some of the songs in the Ainu language.

There are many people in the harmony section of Himekami, mostly from the Tohoku region of Japan, the exact number of people is unknown, but they are a choir - [Himekami Voice].

My knowledge is limited, so I recommend you read this article, which will give you a more comprehensive understanding of [Himekami].