I remember being really scared by a few Are You Afraid of the Dark episodes...
Disclosure: I translated Imamura's Death Among the Undead and Death Within the Evil Eye.
Dispel is the first original full-length novel written by Imamura Masahiro that is not part of his Hiruko series (and coincidentally, by a different publisher). I adore the Hiruko novels of course, and I even translated them, so when I heard Imamura was going to write a non-related novel, I was really excited, as I knew the kind of gold he writes. The summary of Dispel also caught me at once, as I love my "seven mysteries of [locale]" trope in Japanese fiction. In terms of mystery fiction, there's of course the famous Kindaichi Shounen story that serves as the anime and live-action series' pilot, but I'm also for example a big fan of the horror game series Gakkou de Atta Kowai Hanashi ("Scary Stories at School"), a long-running series where you get to hear about seven ghost and horror stories set at a certain school. Knowing how Imamura mixes the supernatural with tightly plotted mysteries in his Hiruko novels, I therefore was more than thrilled to start with Dispel.
The book is quite different from the Hiruko novels though. First of all, the book is definitely written with a younger audience in mind, using the elementary school students Yuusuke, Satsuki and Mina as the protagonists. While they don't always talk and act as actual children, they do cope with problems appropiate for their age/phase in life, and that coupled with the simple narration from their point of view, it's clear Dispel was written for a juvenile ~ TA audience. As said, the three don't always come across as a real children because they are a bit too clever/quick on the uptake and feel more like older teenagers at time, but the way the three all have their growth arcs as they tackle this mystery while preparing to graduate from elementary school is something some readers might find very attractive.
As for the mystery, Dispel is surprisingly very oriented on the seven mysteries of Okusato. Every two weeks or so, the members of the club travel to a different location in Okusato to investigate one of the stories left by Mari, hoping to find out why she was investigating these variants of the stories. These stories function both as a ghost story, as well as a mini-mystery episode. As horror stories, they sound just familiar enough to recognize as "classic urban legends/ghost stories", but with enough unique details to keep you interested in the story itself and fans of urban legends and Japanese ghost stories will probably find them entertaining. Each time, the trio realize something in the story as left by Mari is actually a hint to something else, something they only notice when they visit the place in question. Some of these hints are pretty clever, and thus the ghost stories work pretty ingeniously as "mystery stories", as the reader is required to compare the scary story with reality, and has to figure out 1) what is actually not the same as the story and 2) try to explain what this difference actually means. While some of these questions are a bit open-ended, so hard to explain solely from the reader's point of view, it's stil fun seeing basically folklore study methodology applied to these stories, and often, the revelation feels quite satisfying. These revelations of course chain into some bigger revelation, all tied to Mari's death.
What is interesting is that the book also follows a structure reminiscent of Hayarigami, with Yuusuke preferring a supernatural explanation, Satsuki a rational one, and Mina acting as the judge. As the story progresses, we see both Yuusuke and Satsuki proposing their own explanations to the mystery and also attacking each other's arguments, and for the longest time, the reader honestly never really knows whether there's a rational explanation, or whether there perhaps really is something supernatural (but fairly clewed) going on. Mina works well as a fair judge, not favoring either side and willing to poke holes in both Satsuki and Yuusuke's theories. The book really keeps things thrilling until the end regarding who'll be right, and while with a lot of mystery authors, you'd be inclined to believe the "rational" will automatically win at the end, it's the fact we know Imamura of all people is writing this, that makes this work: you know he's not afraid of using the supernatural, but that doesn't mean he will use it, so you honestly don't know until the end.
To be honest though, I thought the actual explanation to how it was all connected to Mari's death was less interesting than the whole journey to the revelation. Finding glimpses of what seemed to be pointing to a bigger truth with each story worked better for the 'urban legend' atmosphere, than actually revealing everything at the end, I guess, but then again, this is still a mystery novel so you can't really skip this part....
Overall, I did find Dispel an enjoyable novel though. It is certainly a very unique work, and I don't think I have really read any mystery novels that follow a similar structure, something like a hidden treasure hunt within a kind of short story collection. While I don't think Dispel was as good as Imamura's Hiruko novels, it's still a fun horror-focused mystery novel aimed at a younger audience, and I am looking forward to seeing him fan out even more in the future!