Triangle Heart is a series of OVAs and hentai games, and the name comes from the fact that the story focuses on a "triangle." The "triangle" consists of one boy and two girls; however, there are many other heroines besides the girls featured in the "triangle." The OVA is based on the third game, Triangle Heart 3; the actual name of the OVA is Triangle Heart ~sweet songs forever~.

The hero of the OVA is Kyoya Takamachi. He fights with the Mikami-ryuu and Fuwa-ryuu sword styles, and is teaching his sister, Miyuki. While Miyuki doesn't truly feel passion for sword fighting, she does it to honor her adopted father (who was a bodyguard that was killed). Kyoya also runs a cafe in Japan called Midori-ya.

The siblings are friends with Fiasse Crystela, a famous singer and heiress. Fiasse is being targeted by terrorists, while serving as the headmistress for the Crystela Song School that's located in England. Ellis McGaren is Fiasse's bodyguard, who is jealous of Kyoya and Miyuki when they join in to help protect Fiasse.

Shinobu Tsukimura is Kyoya's girlfriend, and she works at Midori-ya. Other employees at Midori-ya are two waitresses who are also martial artists (Akira Joshima and Ren Lianfei), Momoko Takamachi (Kyoya's father’s second wife, and she owns Midori-ya), and Nanoha Takamachi (Momoko's cheerful 12-year-old daughter). Nanoha later becomes the main character in a spinoff series, Magical Girl Lyrical Nanoha.

Triangle Heart ~sweet songs forever~ has some very well-done animation. However, the story can be a little hard to follow, especially if you don’t have any familiarity with the game on which the OVA is based.

A big point of confusion is what genre this piece falls in. On the one hand, you get the impression from the first few minutes the series is going to be some kind of a school-based drama with a minimal amount of violence, since it's set at the Crystela Song School, and all you see are people talking. Then, it suddenly switches to Kyoya and Miyuki in a training session in Hong Kong, which shows the siblings stabbing people, shooting guns, and other violence; however, the violence is not gory, and no blood is seen. Then, it moves to the cafe, where you get some light-hearted comedy thrown in.

If you enjoy anime that seems to be combining several genres, then you might appreciate Triangle Heart. However, it should be noted that there is a shot with nudity included in the first episode. Considering that there is a hentai game series for this property, I would personally recommend Triangle Heart to anime fans who are 18 years of age and older.

Title	Episodes	Release Year(s)	Director	Studio	N.A. Licensor
Triangle Heart	4	2000	Akiyuki Shinbo	Discovery	N/A