I'm a librarian who loves anime, manga, and reading a wide variety of genres.
The one other book by Ayatsuji that I'd read, Another, was interesting enough that, when I heard The Decagon House Murders (originally published in 1987) had been translated, I knew I wanted to read it. In some ways it turned out to be better than Another, but in some ways it was worse.
In The Decagon House Murders, we have a setup in which seven friends who are all part of their university's Mystery Club decide to spend a week on Tsunojima Island. They stay in the Decagon House, a house built in a decagonal shape. It had been designed by the island's previous owner Nakamura Seiji (the translator left all Japanese names in their original order).
Just as Seiji had designed the Decagon House so that it and everything in it, including the mugs in the kitchen, was decagon-shaped, so had he also designed the Blue Mansion. It and everything inside it had been entirely blue. However, it had burned down a while ago. The way the story went, Nakamura Seiji's gardener had killed Seiji's wife and cut off her hand, then killed Seiji and a servant couple that lived in the house, and then burned the entire house down. The gardener had never been found. The Mystery Club thought it might be interesting to stay on an island where such a thing had occurred, just a harmless thrill. However, on the second day they discover seven plastic plates with “The First Victim,” “The Second Victim,” “The Third Victim,” “The Fourth Victim,” “The Last Victim,” “The Detective,” and “The Murderer” painted on them.
Meanwhile, Kawaminami, a former member of the Murder Club, has received a strange letter claiming that Nakamura Chiori had been murdered by “all of you.” Chiori, another Murder Club member, had died over a year ago, from a combination of alcohol poisoning and a bad heart. Kawaminami learns that another club member got a similar letter, prompting him to begin investigating. Was it really sent by Nakamura Seiji, Chiori's father? And if he's still alive, then what really happened in the Blue Mansion?
This book took ages to become interesting. The little plastic plates didn't actually appear until about a third of the way through. The first half of the book was all about setting the stage and introducing the characters, most of whom I kept mixing up. The only ones I was able to easily remember were Orczy and Agatha (all the Murder Club members had literary nicknames), and that was primarily because they were the only women.
If I hadn't pushed myself, I probably would have given up before the second half, when things finally started heating up. The beginning of the book referenced Agatha Christie's And Then There Were None, and there were several similarities between that book and this one. The would-be murderer put his confession in a bottle and threw it in the sea, the Murder Club was trapped on an island with no way off and no rescue coming anytime soon, and the plates functioned like the little porcelain figures in Christie's story, letting the characters know that another person had been killed.
However, as the story progressed, I started to wonder if the reference was actually a red herring. Was Nakamura Seiji really still alive? Was he hiding on the island, murdering those he believed had forced his daughter to drink herself to death? Or was Nakamura Seiji's brother really the one behind it all, somehow murdering people on the island despite speaking with Kawaminami, Morisu (a friend of Kawaminami's and another Murder Club member), and Shimada (a friend of Nakamura Seiji's brother)? I already knew from reading Another that Ayatsuji wasn't above cheating a bit, so it was quite possible he had twisted certain details to suit the story.
I didn't see the ending coming at all, and I'm not sure it would have been possible to deduce it, even though Ayatsuji sprinkled hints here and there. However, unlike in Another, I wasn't left feeling that he'd cheated – that's why I said that, in some respects, this book was better than Another. Another had a more interesting setup from start to finish, but The Decagon House Murders was more cleverly constructed. One particular revelation near the end had me flipping back to earlier passages, trying to find a point at which Ayatsuji had lied to the reader or otherwise messed up, but it actually all fit together very nicely. Although, dang, the murderer probably came very close to dying along with everyone else at certain points.
All in all, I'm glad I read this, even though the first half was a bit of a chore to get through. It was slightly dated - no cell phones, no Internet, and several mentions of few people having word processors of their own - but that aspect didn't interfere with my enjoyment of it. It was a fascinating mystery, and I liked that Ayatsuji opted to bring up the confession in a bottle again at the end.
The book begins with an introduction by Shimada Soji, which discusses some of the history of Japanese mysteries, as well as The Decagon House Murders (which was Ayatsuji's debut novel) and its reception.
(Original review posted on A Library Girl's Familiar Diversions.)