YT description pretty much covers why to watch this:

Broadcast on the NHK in 1974

Shoichiro Sasaki is a masterful director who influenced an entire generation of Japanese filmmakers (Iwai, Kore-eda, Kawase, Tsukamoto, Anno, Hosoda, etc) but, due to spending a large chunk of his career working for the NHK--Japan's national broadcasting channel--nearly all of his filmography has gone without physical releases and without subtitles, leaving him a complete unknown in the English world.

So enjoy some rough, artless subs I made for his classic, Dream Island Girl. You can almost immediately feel the influence he had here (Dream Island Girl oozes "Hideaki Anno watched it" energy), the movie shot and edited like something that wouldn't exist for another 20 years. This is also where Sasaki discovered Sachiyo Nakao, who would be the lead actress in several of his movies, and who only acted when he directed until very recently, when Mamoru Hosoda convinced her to lend her voice to his movie Belle!

It's great, it's powerful, and I hope you like it!