The Snake Girl and the Silver-Haired Witch

The Snake Girl and the Silver-Haired Witch is a 1968 Japanese horror film directed by Noriaki Yuasa. The film is about a young girl named Sayuri who is reunited with her estranged family after years in an orphanage, but discovers that her homelife involves an amnesiac mother, her sister is confined to the attic, and begins to wonder if this is related to her father's experiments with poisonous snakes.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.