Originally appearing in Japan as Yogisha X no kenshin in 2005, and winning the Naoki Prize of that year, The Devotion of Suspect X has recently been published by Minotaur Books in the U.S and is also forthcoming by Little Brown in the U.K., the translation is by Alexander O.Smith and Elye J. Alexander. Unlike Naoko that has at it's centre a fantastical idea, The Devotion of Suspect X opens with a description of events that lead up to a murder and then presents to the reader the perspective of the police investigation from the moment that the body is discovered and then follows the investigation as they decipher clue by clue, deduction by deduction the circumstance and culprits of the crime, and behind this a cryptic game of cat and mouse between two geniuses. There's a blank in the narrative between the initial aftermath of the murder and the discovery of the body, which the novel is used to slowly unveil to the reader. Ishigami, a private high school maths teacher leaves for work on his bike stopping off at a boxed lunch store on the way, working at the boxed lunch shop is his neighbour, Yasuko Hanaoka, a single mother who has a daughter, Misato. Yasuko had been divorced a few years earlier from her husband Shinji Togashi, although Togashi is not Misato's father, Yasuko's boss jokingly implies that Ishigami fancies Yasuko, that's why he stops by everyday. Out of the blue Shinji Togashi enters the store and begins to harass Yasuko into meeting again, after repeatedly asking him to leave her strength of will gives way and she says she'll meet him after work. When they meet again Yasuko reiterates that she doesn't want to see him again and that he should stop pestering her, despite Togashi saying he is a changed man, Yasuko leaves abruptly. After Yasuko has been home for a while Togashi starts ringing her doorbell, knowing that what he probably wants is money she reluctantly lets him in on the proviso that he leaves after she has given him 20,000 Yen. But on his way out Misato in a rage fuelled by some his comments smashes him over the head, in retaliation he lunges at her, fearing that he will kill Misato Yasuko strangles him with the kotatsu cord. At first Yasuko is going to hand herself into the police but Misato tries to persuade her out of it, the conversation is disrupted by her neighbour Ishigami knocking at the door asking what the noise was about. Yasuko at first manages to disguise the fact of what has happened from him, but Ishigami calls again later revealing that he had actually heard everything, and to Yasuko and Misato's surprise he offers them his help in covering up the murder.
The narrative turns to the police detectives Kusanagi and Kishitani who get a report of a body being found, an attempt has been made on the body to make identifying it impossible, and nearby police find clothes that have been partially burned and a stolen bicycle, these are the circumstances that the detectives slowly piece together. Through their enquires and forensics they learn the identity of the man as being Shinji Togashi. The detectives inform Yasuko of the murder and while they are at her building they bump into her neighbour Ishigami who they also talk to, through a letter in his mailbox Kusanagi notices that Ishigami used to attend Imperial University. Another central character to the police investigation is Yukawa, (whose nickname is Galileo - the name of the Japanese T.V serialization of this novel), a professor of physics, who Kusanagi sometimes refers to for help in solving cases, Yukawa also attended Imperial University and as the case progresses he comes into contact again with Ishigami, as a friend, and at a distance as a suspect. Whilst at university Ishigami earned the nickname 'The Buddha', as he was always hunched over his work trying to solve mathematical problems. The main corpus of the novel traces the police as they try to break the alibi of Yasuko and Misato, which was given to them by Ishigami, who keeps tabs on Yasuko and Misato by phoning them from a public phone booth every night. After time Yasuko begins to wonder why Ishigami helped them the way he has. As the narrative holds back from giving a vital clue and doesn't reveal the chain of events between the murder and the finding of the body the suspense is brilliantly drawn out, and just like in the earlier novel Naoko/Himitsu, Higashino has a great skill at shifting the parameters of these novels at the crucial moments, keeping the reader guessing until the last few pages have been turned.