The body under the Decagon House is the gardener, whom Seiji likely killed and hid there, or the gardener tried to escape but Seiji killed him there.

Seven friends venture to an isolated island for a week of bonding over their shared love for detective fiction. They both have students going to a remote island where they’re killed off 1 by 1 and both openly pay homage to Agatha Christie’s original. Obviously nothing goes wrong and they spend a relaxing week long vacation, talking about books they like and taking in the sun… oh, wait, no, this a mystery novel. And that kind of character is either totally suspicious, or being set up to be an eccentric series character. The cookie is set by Facebook to show relevant advertisments to the users and measure and improve the advertisements.There just has to be a better way of ending the book that explains the beautiful puzzle but also packs a bigger punch. The next morning, a female student is found strangled with her left hand missing (like Seji’s wife) and the plaque with 1st victim glued to her door. He sent the letters to everyone, and then kept the original for himself, only cutting out the phrase “Chiori was murdered” to remind himself of why he’s doing all of this. Meanwhile, back on the mainland a former member of the club named Kawaminami receives a letter saying that the death of a girl who died at a club party one year earlier was murder. The puzzle it poses and solves is of great quality, and the parts of the novel dedicated to the island inhabitants and their growing anxieties and paranoia are particularly compelling.

All nine mystery club members received letters saying “My daughter Chiori was murdered by all of you. Meaning all clues are given, so despite the improbability of the crime, you, the reader, could in theory solve it as well. The members of the mystery club are excited to stay at the decagon house, uncover clues and discuss theories to determine what really happened.When Seiji the architect and his household died, the fifth member of the household, a gardener, disappeared. While they are away on the island, a former member of the mystery group, Kawaminami receives a mysterious letter that points out his connection to a former student Chiori, who died. Soon after their arrival they begin to suspect that one of their members is intending to kill them one at a time, but who? The characters are remarkable, the story is intriguing, and I loved reading about how things pan out.

In one way, this made it feel less like your classic mystery, and more like a slasher movie, where you just watch with curiosity on how the teens will be picked off by our killer next.

The Decagon House Murders ( 十角館の殺人, Jūkakukan no satsujin) is a 1987 Japanese mystery novel, the debut work of author Yukito Ayatsuji. Seven students, members of their university's mystery club, decide to spend a week-long vacation on Tsunojima Island off the coast of Japan. Kodansha collected its chapters in five individual tankōbon volumes, released from November 22, 2019, [6] to May 23, 2022. I don't have that reaction very often; even though there have been many times I've been truly surprised at the unmasking of the who, this one absolutely takes the cake. But here the characters were bland, the girls left a lot to be desired (they are the type of characters that would have been okay-ish if they existed in a 1930s whodunnit) while the boys (allegedly) were all kind of clever and yet so very foolish and slow.