This short manga is real short, having only 6 chapters, in one hour or less you can read this full. This was also an adaptation of the movie.
Jisatsu Circle, is described in 2 words: Disturbing, Horrible. The theme of Suicide is the main core of this horror manga, and added some atrocious behavior, and illustration.
Story - Jisatsu Circle has an easy to comprehend plot that is about suicide. At first the plot will make the reader think why they did that, and the story progress through that. There is one survivor of the incident and she is the main character of the manga. The only problem with this is most of the time the story depicts horror, not essential plot and information. Most pages were filled with filth, gore, ew, yuck, pages that can make the manga 'horrific', but at the end made it 'horrible'.
Decent graphics, nudity (topless), and some visual violence (sexual, gore), The faces are quite forgettable, and some character had a very, very disturbing face.
Characters are very simple, and stereotype. They are made to die (given the background, behavior, and nothing to think about them.) Supporting characters are doing their role, and most of the time they are really sinister, not telling they are just school girls.
Jisatsu Circle is a decent manga to read. You can burn time reading it, it is not really scary. You must just prepare for the graphic violence.