The Pillow Book of Lady Wisteria

Samurai sleuth Sano Ichiro has a very personal motive in determining who killed the shogun's heir apparent with a hairpin: he's trying to save himself from being executed for the crime.

The Pillow Book of Lady Wisteria introduces readers into Yoshiwara, the well-ordered but cruel pleasure quarter of 17th-century Edo (Tokyo), where the corpse of Lord Mitsuyoshi is found sprawled on a bed. The woman with whom he'd spent his final hours, a top-ranking courtesan known as Lady Wisteria, has disappeared, along with her private journal, which might supply clues to her complicity in this slaying. In the absence of both, and with the capricious old shogun ordering that Mitsuyoshi's family not be quizzed about his death, Sano is left to look for assassins among the courtesan's attendants and prominent clients. Meanwhile, Sano's enemies vie for credit in solving the murder (even if they must pin it on Sano), a woman's headless body is found wearing Wisteria's kimono, and Sano's amateur investigator wife, Reiko, threatens to discover the link between her samurai and the enigmatic prostitute.