The Decagon House Murders

The Decagon House Murders is a mystery novel by the Japanese writer Yukito Ayatsuji, published in 1987 and his debut. It belongs to the honkaku school of puzzle-based detective fiction.

Seven members of a university mystery club travel to a deserted island that holds a strange, ten-sided house. The book's basic structure is borrowed from Christie's And Then There Were None, and the students themselves refer to Christie as the events turn.

Six months earlier the island was the scene of a mass murder, and the deaths there were never explained. Then the students begin dying one by one, and it becomes clear that whoever is doing it is on the island with them, so the puzzle turns on working out who among them is responsible.

Ayatsuji helped revive the classic puzzle mystery in Japan, and the book was one of the titles that led to an English-language edition in 2015. It was later adapted into a manga.