卍の殺人 (manji no satsujin, The Manji Murders, 1989) is IMAMURA Aya's first novel. The manji of the title is the Japanese word for the symbol that in English is best known as the swastika, although the symbolism is different to the Nazi version that comes to mind. The shape is different as well, in that the arms bend counter clockwise. A character in the book says that the other direction brings associations with Nazism in Japan too. The symbolism is fairly irrelevant here, because the sign's only role is as the shape of the house of a rich Japanese family. This is one of those stories written in the boom of "new orthodox" detective stories, that try to recreate the golden age (in this cases also emphasising particularly elements that YOKOMIZO Seishi had favoured): a closed circle of suspects in an isolated mansion; unusual architecture; intrigue centred on a wealthy family; impossible crimes and crimes with a pattern.
The mansion in this case has two branches of a winemaking family, each living in a different arm of the manji of the title, with a common hall in the middle. ANDOU Takumi (安東匠), ｔhe adopted son of one of the families is making his own life as an illustrator in Tokyo and has a new girlfriend HAGIWARA Ryouko (萩原亮子) in the narrator, a translator. The head of the family has summoned him home to discuss marrying his cousin; but he declares that he will give up his place in the family, and travels with his girlfriend to explain his intention to marry her. On the first night in the mansion, Ryouko witnesses a man in the other wing of the mansion strangling a woman. That turns out to be only one of two murders that night, as in a different wing another victim has also been strangled. This is the first of a series of deaths and attacks; and the same pattern of nearly simultaneous victims in different parts of the house repeats itself.
The various crimes involve a series of tricks. For many the characters, particularly Takumi, find a solution to the mystery early on, only to overturn it with a new complication later. A locked room mystery is quickly dispensed with one solution, then another. The plausibility of some of these tricks demands generous readers. The final revelation proves to be a variation on a very familiar trick, but a bold one, and so thoroughly signalled throughout the book that a reader who has not spotted it (I hadn't) will be impressed. This is certainly no classic, but a respectable minor honkaku mystery.
[UPDATE: One point I forgot to mention. I read this in the kindle version, and the various floor plans and family trees in the book were unreadable. Clicking on them made them larger, but equally illegible. If you're thinking of reading this, you'd probably do better with the paper version.]