The Decagon House Murders [1987/2015] – ★★1/2
This book, translated from the Japanese by Ho-Ling Wong, “was seen as a milestone in detective fiction and the start of the shin honkaku (new orthodox) movement” [1987/2015: 228]. That movement was a revival of the traditional “logical reasoning” detective fiction in Japan that was prevalent in the Golden Age of detective fiction in the 1920s. The new movement was characterised by robot-like personages; game-like setting; and lacking literary context or significance, being purely about solving a whodunit mystery using logical reasoning. Heavily influenced by Agatha Christie’s And Then There Were None , The Decagon House Murders is about seven Japanese students who decide to stay on an isolated island not far from the main land in a mysterious Decagon House. Some months previously there occurred on the island the mysterious deaths of the owner of the property, his wife and their two servants. The students on the island are then start to be killed off in a fashion reminiscent of that in Agatha Christie’s famous novel. The book premise is exciting, but the book also reads like a videogame script with little character insight, context or emotion (which is intentional, but may not be for everyone), and the final solution is, arguably, too unbelievable and underwhelming.
The story starts intriguingly. Seven students (five boys and two girls) of K-university arrive to an island not that far from the main land for a week to get some inspiration or write their own stories of mystery. They are all members of the Mystery Club at their university, and the island to which they arrive is the place where horrific deaths of the owner of the house Nakamura Seiji, his wife and their two servants happened some time previously. In the centre of the island is the eerie Decagon House, which is described as “the decagonal trap” [1987/2015: 16] unbeknown to the students. The seven students also do not know that there is someone who wants to harm them and what awaits them on the island is the very thing that they are so excited about when they read and write their murder mysteries. Meanwhile, events also happen on the main land and the acquaintance of the seven students on the island – one Kawaminami Taka’aki receives a scary letter accusing him and other students of the death of another young female student who died from alcohol poisoning some time before. Kawaminami starts investigating and the connection with the isolated island events is revealed.
The book makes it very clear and explicit that it takes the story setting and other major elements from Christie’s novel And Then There Were None. It never shies away from its source material and even could be said to pay a tribute to the novel by Christie. They are many obvious similarities between the two to the point where The Decagon House Murders may even be considered a parody book. The setting of an isolated island, the bottle with a message, few suspects and the great design/plan by the murderer revealed at the beginning are just some of the more obvious similarities. In fact, And Then There Were None is explicitly referenced at least twice in Ayatsuji’s story, and the story also pays its indirect tribute to other traditional mysteries of the 1920s crime fiction by giving each of the seven students in the novel the nicknames of the famous mystery writers: there are Ellery, Carr, Leroux, Poe, Van, Agatha and Orczy who arrive to the island. For example, Agatha stands for Agatha Christie, the Queen of Crime, and Leroux stands for Gaston Leroux, a famous French crime author.
The Decagon House Murders is an interesting read and it is exciting not to know who the murderer is, waiting for the final reveal (it is also great that the book provides diagrams/plans of the isolated island and the Decagon House). However, it is also true that the book has no to little literary merit, context provided or character insight. Following the seven students on the island is like following seven puppets in some tacky theatrical show who get murdered without emotion or consequence since they are not “alive”. It is probable that the book then influenced other computer, anime-like book genres, maybe even including the infamous novel Battle Royal  by Koushun Takami, on which The Hunger Games  was based. The unremarkable language used to tell the story, as well as the “cold” approach to story-telling and murders in The Decagon House Murders is, of course, intentional, but that is not even a major problem. The “logic” in the story can be challenged. The ending is unforeseen, but the murders happen in too unbelievable a fashion, and the constant shifting between the main land events and the island occurrences does not work successfully because the island events are much more exciting. Moreover, it is something outside of the picture and nearly impossible to accomplish which finally points to the solution, meaning that the ending is also underwhelming.
The Decagon House Murders is a spooky and sinister tale which is interesting to read, but it is also ultimately a let-down because of its own ambition, being too unbelievable in its proposed solution and not coming even close to Agatha Christie’s quirky logic in And Then There Were None. The book also has a narrative which quite intentionally lacks any context, emotion or character insight, being almost an anime script filled with endless dialogues and crime theorisations. Its “clinical” style has and will have its fans, though, even despite the lack of detective fiction novelties.