The song is 彩虹山(Rainbow Mountain) by 文雀(Sparrow).
What is the instrument playing the repeated note in this song starting from 5'25''?
To my limited music knowledge it sounds like violin, but I'm not sure.
Music Fans Stack Exchange is a question and answer site for music historians, critics, and fans. It only takes a minute to sign up.Sign up to join this community
I'm pretty confident that this is a modern synthesizer playing a note from a "string ensemble" setting. It definitely a "string" sound, but it doesn't sound like a solo violin, and it's too perfectly identical each time to be an actual string ensemble.
Older synthesizers had string sounds that were more easily recognizable as fake, but the modern ones sound close enough that the best way to tell them apart is when they sound too perfect.
I hear violin as well but can't tell if it's real violin or synth violin. The most information I found about album personnel (on the album's Bandcamp page) doesn't indicate anyone other than the band members.
Yes, it's either a synth/sampler impersonating a violin, or an actual violin. It's impossible to say which because the only pitch it plays is a high B, and all its notes are equally short. I think it's probably a synth though, because it's so unvarying, each note occurring precisely in time and without any expression. It wouldn't be worth hiring a violinist to do it.