Why isn't this in with D.Gray-man and 100 Bullets? Because I hadn't finished the volume when I wrote that post. And the tildes in the title? That's how it's written on the author information and publisher information page.
Title: Spiral ~Suiri no Kizuna~ (volume 1)
Media: Manga (tankouban)
Story: Shirodaira Kyo
Art: Mizuno Eita
Publisher: Gangan Comics (a Square/Enix publication)
Overall: Honestly, I'd forgotten just how much I liked this series, both in manga and anime form. The subtitle of the series, "Suiri no Kizuna", translates as "The Bonds of Reasoning". (Inference is another translation of "suiri", though not used nearly as often in translating the subtitle. Interestingly, though not surprisingly, "suiri" also refers to the mystery or detective story genre.) This is easily my favorite meitantei (detective) story, though Death Note is a very solid second. In the end, though, Spiral has Hiyono-chan, who is quite possibly one of the most entertaining characters in manga. Spiral is right up there on the must-read list.
For those for whom a Japanese text is a mystery in and of itself, there is an anime version of Spiral released by FUNimation. Unfortunately, the translation isn't of the highest quality (or I'm just picky, having done my own translating for the manga), though serviceable, and the anime only covers the first six or so volumes of the manga. The anime does, however, have an incredibly appropriate soundtrack, which serves to highlight every important moment without getting in the way of the show. The other misfortune is that Tokyopop, the American company which has the rights to the Spiral manga, has been squatting on them, unmoving, since 2005.
The mystery begins two years before the story truly starts, in a short prologue in which Narumi Ayumu receives a cryptic phone call from his older brother, Narumi Kiyotaka: "I'm going to look into the mystery of the Blade Children. Please tell Madoka." Two years later, Ayumu wakes up from a dream fitting this description, late for his afternoon classes, only to end up fingered for a murder he did not commit.
Chapters one through three center on the mystery of how a girl could have been killed from a fall if no one was present to push her, and once the killer was revealed, who killed the killer, and why. The arc closes with the knowledge that the Blade Children mystery is somehow tied in to the first killing. Meanwhile, chapters four and five begin a locked room mystery quite as unfathomable as the one depicted in Sir A.C. Doyle's "The Sign of Four".
The characters make the series, with even the best of them having their flaws. Ayumu, for example, is an excellent deductive reasoner, but in his own mind, he is forever trapped in the shadow of his brother, Kiyotaka. Beside the brilliant Ayumu, Yuizaki Hiyono is the normal one, both noisy and nosy. Still, though she's neither a natural genius like Ayumu, or possessed of the mystery-shrouded brilliance of the Blade Children, Hiyono holds her own quite capably.
Volume two brings in the first of the important Blade Children, but we'll get to that later.
A few differences to note between volume one of the Spiral manga and the first few episodes of the Spiral anime:
The girl killed in the first volume of the manga actually survived in the anime, and was not done in by fellow students related somehow to the Blade Children, but instead by one of the Hunters (who the manga gets to later). The different outcome is explained by the presence of a delivery truck, which broke the girl's fall early, thus sparing her life.
The Hunter, after he was found out and confronted, was then shot (if I'm recalling correctly... it has been some time since I watched the anime) rather than felled by an arrow, and he didn't die either, but ended up in the hospital where he passed on the information about the plot being related to the Blade Children.
And finally, under the dust jacket, there is a four-panel extra of Ayumu trying to figure out what bothers him about the hand puppets that Hiyono had in chapter two.