I think I found them by association of the genre "post-rock".
I was strolling in Tower Records and marking down the artists that interested me. It's been some time so I don't remember clearly, but it is probably Anoice's album "The Black Rain", or I found it later by looking up the composer. I was amused by the track "self-portrait". Here's one of the other nice track from the album: https://invidious.snopyta.org/watch?v=s3mELa0zSuI
I didn't know post-rock before. The genre "rock" reminds me of the rough and loud noise from heavy metal, but post-rock is entirely different, IMO very emotional. For post-rock I also recommend MONO.
@udon I found them when I was listening to Mili. They apparently made a song together. Mili uses a lot of piano and strings but little electric guitar, so it might be different. https://youtube.076.ne.jp/watch?v=sA5xYUGet2g
That 0 remix and Holy and Darkness 1 are how I discovered arai tasuku. If there's Holy and Darkness 1, shouldn't there be Holy and Darkness 2 in the future? That would be great.