[Japanese > English] "Hatachi no Etude", old japanese book, I think.

Hey so, I was reading a translation of Ichigo Doumei a few years back and found the tittle to this "book" and I say it like that cause I haven't been able to find much info on it up until today, when a redditor helped me with this Japanese site or archive. I'll link it here because I'm not sure what any of it means, and if anyone could help, it's a book by an author who committed suicide shortly after. He was 19 years old and this was his last writings. Thanks in advance.

Link: https://www.aozora.gr.jp/cards/000740/card49078.html