Dear Brother (Onisama E), (39eps. x 25m)
Onisama E is set in a private school for rich girls, the Seiran Academy, and is the story of Nanako, a professor's daughter & nice-but-ordinary girl, and how she fares there. The 'Dear Brother' of the title is an absent brother to whom Nanako composes diary-like letters telling him about her troubles. The school has an exclusive sorority, membership to which confers many social privileges (and also benefits such as extra tuition), and membership is eagerly sought after. When Nanako is admitted, other girls are consumed with rage and jealousy, and make life almost intolerable for her. Nanako is befriended by a beautiful girl, Mariko, who proceeds to undermine Nanako's friendship with her kindergarten friend Tomoko, and whose feelings for Nanako go far beyond friendship...
Then there are three girls with strange nicknames: "Saint-Juste-sama" a disturbed girl, so tall and slim that Nanako initially mistakes her for a boy, Kauro-no-Kimi, tall and athletic, and opposed to the Sorority, but ill with heart trouble, and "Miya-sama" the chilly leader of the Sorority. Saint-Juste is hopelessly obsessed with Miya-sama.
Kauro-no-Kimi befriends Nanako, who also is fascinated by Saint-Juste and tries to help her.
It's no exaggeration to say that this is one of the most beautiful anime series I have ever seen, with very detailed character design. It's a drama, with none of the attempts at humour which are ubiquitous in recent anime, and contains some fairly shocking elements; indeed the series is, as soon becomes obvious, largely about intense female friendships, (which some will interpret as lesbianism), as well as about hazing and the less pleasant things that go on in schools.
The series was clearly aimed at older girls and is frankly unsuitable for juveniles. It was shown briefly on Italian and French TV but proved too much even for these liberal regimes and was respectively cut and axed.
Now visit the Techno-Girls' site, which is the only other substantial source on the Internet of Onisama e information. The Techno-girls also did the only available fansubs (#1-#12). Their site has a list of distributors.
There was a manga by Ryoko IKEDA of "Rose of Versailles" fame, but this is currently out of print. No complete set of episode translations or synopses for the anime seems to be available, but I do have a manga synopsis. The anime story is an expanded version of the manga story, and the two do not differ radically. I presume that there is a laserdisk set for the series, which you might investigate if money is no object.