It's been a while since I talked about a Himura novel here, so I'll just repeat this even just to be sure: the mystery novelist Arisugawa Alice has two main series, both of which have have a character named Arisugawa Alice as their respective narrators. These two Alices however are not the same person. The Alice in the Student Alice series is a young student who acts as the Watson to the older student Egami (see: The Moai Island Puzzle) , while in the Writer Alice series, we follow an Alice in his thirties who's a professional mystery author, who acts as the assistant to Himura Hideo, a criminologist. The funny thing is that these Alices write each other: the student Alice is a budding mystery author who writes about a professional mystery author named Alice and his friend Himura, while the writer Alice writes about a young student named Alice and his senior Egami. Anyway, Karyuudo no Akumu is of course a book about Himura and Alice. This series is much longer than the Student Alice series, and to be very honest, this is reflected in quality too: while seldom bad, the Student Alice series is consistently extremely good in terms of mystery plotting, clewing and doing Queenian reasoning chains to identify the murderer. The Writer Alice series has its own gems of course, but as it also has like at least triple the number of releases, you can understand how it is not as consistent in terms of quality.
So what is Karyuudo no Akumu? Well, that's a hard one to answer! I have mentioned more than a few times here that in principle, I am more a fan of short stories than of novels and it's something I felt very strongly as I read this book. Which is a very personal thing of course, but this book has a very limited setting and set-up on purpose, which can make the book feel very slow, because it has too few pieces to move around or to check. Some might prefer the more focused approach, and there's definitely also a reason why this story has such a focused set-up, but to be very honest, as I was reading this I constantly thought the same set-up could have worked just as well, or even better as a short story or a novella, especially as this book is actually bit longer than average, rather than shorter. And as I arrived at the conclusion and followed Himura's reasoning as he very logically identifies the murderer, I still felt that considering the clewing and the other relevant factors for the mystery plot, the story of Karyuudo no Akumu would have worked in a far shorter form too. So that is definitely something that plays in my impression of the book.
For as a mystery story, I do think Karyuudo no Akumu has some good moments. Some really good moments even. For most part of the story however, you feel like Karyuudo no Akumu is just trying to juggle with too many pieces, despite the very, very limited set-up and there really aren't that many pieces. The cast of characters is very small for example, focusing mostly on the six people living on along the road (which had been blocked off from the highway on the night of the murder due to a thunderstorm striking a tree which fell across the road). So the mystery in terms of characters and location focuses solely on that little road, but at the same time, we are also confronted with many smaller mysteries: a cut-off hand, a woman who for some reason was killed with an arrow, what was the woman actually really doing staying in the cottage, where are her hand and smartphone and more. At the same time, these problems don't feel as "big" as say a locked room murder, missing footprints in the snow or even a situation where everybody has an alibi. So these problems "bug" you but are not very effective in really driving the investigation. As the story unfolds, we learn more about the victim and who might have had a motive to kill her, but Karyuudo no Akumu mostly feels like it's throwing all these smaller mysteries at you that on their own are okay-ish, but as a result, it does make you feel like you're playing with too many small puzzle pieces that don't seem to connect in a meaningful manner: the book feels chaotic and disjointed at times.
But all the chaos becomes order when Himura at the end explains how all those disjointed pieces are connected. And yes, there's a reason why a lot of what they find out and what had happened feels so haphazard, and while I wouldn't say the logical chain Himura builds here is as impressive as the tour-de-force we saw Egami pull off in The Moai Island Puzzle, it is definitely the same kind of memorable logic that allows Himura to identify who the murderer is: he focuses on all the actions the murderer took on the night of the murder, even those that don't seem to make much sense, and by applying all the known facts he not only manages to explain why everything happened the way they did, but also how those insights allow us to identify which of the suspects is the murderer. The revelations regarding the motive, while totally convincing, are not presented in a manner as strong "logically" but that is not as big a concern as Himura shows who the murderer is based on what everyone knew at what time and what actions they would or could have taken taking that in consideration, showing exactly that only one person could have commited the murder. I do have to say the last step, where he eliminates the last possible candidate to end up with the murderer, is... not weak, but certainly not very strong. Reasoning-wise I totally get what Himura means and it is true it is a valid way to use to eliminate the last suspect, but at the same time it's not a very strong one and open to a lot of attacks, and is of the kind you'd usually more likely to see as a "first step" in the elimination process (like the first suspect is removed because of this argument) rather than the final person. Still, I was quite impressed to see Himura pull everything together at the end of the book, because I felt throughout there were just so many "loose" puzzle pieces I was afraid it would just feel like a messy blob of minor puzzles, but in fact, it all chains together very nicely, surprisingly so, and it's certainly a book you should check out if you like these kinds of Queenian deduction chains.
But as mentioned, had Karyuudo no Akumu/Nightmare of a Hunter been a short story/novella, I would probably have liked it even better. Of course, your mileage may very well vary here, and in that case, I think you'll find a very competently written mystery novel here that showcases Arisugawa's love for Queenian chains of reasonings. While the core case aspects feel a bit limited and perhaps not really exciting, I think the final section definitely makes this book a worthwhile read, as it shows how the emphasis on reasoning can make very chaotically-feeling stories feel very logical in the end and it's definitely one to check if you like these kinds of novels. And while it's a bit late to mention it now, it's actually the reason why I read this book, because I read somewhere this was one of those books where you could really see Arisugawa doing his "chains of deduction" thing, and I was not disappointed in that regard.