There isn't really a lot to say about Uroboros no Wa. No one takes chain letters seriously anymore. Can you do that for a manga about them? Well, let us elucidate a few things first.
First of all. it's not six chapters. It's two volumes, of six chapters each. Each volume is a stand alone story, with a single character connecting those two. Secondly..Horror? You'd be disappointed. Shoujo? Why, yes. Especially the second volume's romance is rather decent.
Talking about the first volume, you can't really expect some real character development in a six chapters story. There's a girl surrounded by bishounen's. She's into her friend who's
always there for her, but she isn't too reluctant to make out with -someone- else in the meanwhile. There are people who get jealous. And there is a cursed letter. If you receive it, you should pass it on to a couple of friends; or you'll be cursed, and this time it's real. Personally, I would have liked the teacher character to be the voice of logic, instead of readily accepting the existence of such things as curses, but oh well. You don't need me to spoil what lies beneath the cursed letters. If you've seen any japanese horror movie (or something like that), you should know.
The second volume takes us a year later. This time around, Masami-kun, the youngest of the three bishounen brothers, is the main character. He's still the headstrong teen that will go after the girl he likes, no matter what. The artwork is the strongest point of this manga. And Shiori, the girl with the overprotective male around her, is really pretty. As Masami and Shiori get drawn together, they will have to deal with another curse. Only this time, the curse isn't used to fail in scaring us. It is making us sympathise with the young lovers instead. It is emphasising their feelings for each other, and Uroboros no Wa inches further closer towards the shoujo genre. Hooray.
Is it enjoyable? Sure, if you like short stories that involve romance, love triangles, some bullying. As for the "scary" moments? It will be as easy to forget them, as it is to delete a chain email.