I'm reading ... The Decagon House Murders

A group of university students, members of their school’s mystery club, spend a week on an uninhabited island, the scene of a gruesome murder-suicide the year before. They’re camped out in a small ten-sided house, the only building still standing after a mansion on the island burned down during the previous crime.

This novel was written by Yukito Ayatsuji and published in 1987, an exemplar of the shin honkaku genre of modern Japanese mysteries influenced by the golden age. Both of the shin honkaku novels I’ve read (including The Honjin Murders) are locked-room mysteries, and The Decagon House Murders was clearly riffing on Agatha Christie’s And Then There Were None.  

For some reason, almost everything in the mystery genre is being compared to And Then There Were None these days. If a book is set on an island, or has a limited cast of characters, or involves people cut off from civilization without cell phones (avalanche-prone ski chalets are particularly trendy) the comparisons begin. As a snob and an avid Christie reader, I don’t think there’s a great understanding about what a locked-room mystery really is, possibly because for writers this style is fiendishly difficult to pull off without absolutely absurd machinations (see previously mentioned Honjin Murders). If the person doing the murdering isn’t actually in the locked room with the murderees, it’s something, but it’s not a locked-room mystery.

And Then There Were None is also the most suspenseful of Christie’s novels, I think the only one that successfully played with suspense. It’s compact, clear, and gives readers a sense of justice served within a few short scenes. It’s said a lot, but I think this novel is a true masterpiece. 

The Decagon House Murders is one of the most successful modern tales in this genre that I’ve read, not quite up to And Then There Were None, but much, much better than many imitators. It follows all the rules and ends in a true twist that is allowably far-fetched, but fully explained. I guessed the solution about three pages before it was explained in the novel, and though I didn’t quite guess who, I guessed how. In her newsletter Read Like the Wind, Molly Young calls this a puzzle draped on the framework of a novel, which is fair, and compares it to Ellen Rankin’s The Westing Game, also fair.

The Decagon House Murders ends with 32 pages of explanation, every detail described, sort of omnisciently, as if the murderer were thinking about how s/he pulled it off. As I wind up what I hope will be the last draft of The Hanging Valley, I’m struggling with how to end effectively, how to bring readers into the full explanation of what came before, while still maintaining the rhythm of the narrative. This is an attempt to avoid the info dump that ends Decagon, to make it a novel, rather than a puzzle in the shape of a novel.