What type of Japanese classical orchestration is being used to make this song?

I am not an expert by any stretch of the imagination, but I believe that flute is a shakuhachi. I do not know if there were other traditional Japanese instruments or not.

I agree with Jake. Might be shakuhachi there at the start of the song. I don’t hear any other Japanese instruments (shamisen, koto) being utilized…just violins and flute.
Honestly, as a flute player, I think it’s possible a ‘regular’ flute (as opposed to shakuhachi or wooden flute) could have be utilized, too..might just be a regular orchestra that played that first 30 seconds.

I wish I knew and could help you. I will send the link to my son. He’s a grad of Berkeley College of Music in film scoring and performance. Maybe he will know. But thanks through the tears for posting that link. How moving.

Sounds like traditional Noh music. Maybe the particular “melody” is funereal. Similar can be found in first segment of Akira Kurosawa’s Dreams in which a child witnesses a surrealistic death procession and then is barred from his home.

Noh hayashi ensemble consists of four musicians, also known as the “hayashi-kata”. There are three drummers, which play the shime-daiko, ōtsuzumi (hip drum), and kotsuzumi (shoulder drum) respectively, and a shinobue flautist.

Although it could be shinobue flute [as suggested above] and taiko drum performing a similar funereal segment.

In last sentence previous post, I meant shakuhachi as said by @hawaii_jake and @geeky_mama but ran out of edit time . . .
shakuhachi flute and taiko drum