After a 2008 Japanese adaptation, a 2012 Korean adaptation, and before a planned American adaptation, comes the Chinese adaptation of Keigo Igashino’s crime novel The Devotion of Suspect X, directed by actor/singer and second-time director Alec Su. This will be a review of the film as an independent piece of work; for insight on how it compares to both the source novel and the previous adaptations, head to Maggie Lee’s review.

Shi Hong (Zhang Luyi) is a brilliant but asocial mathematician, a listless high school teacher whose only affection – albeit undeclared – is to Chen Jing (Ruby Lin), a single mother who lives with her daughter in the apartment next to his. When one day her abusive ex-husband is found dead on a river bank, his face caved in beyond recognition, Cheng Jing becomes the prime suspect, but police consultant Tang Chuan (Wang Kai) recognizes Shi Hong as his childhood friend, with whom he used to share his love and skill for mathematics, and senses he may have something to do with the murder. A game of chess starts between the two old friends.

Eschewing the traditional detective story template, The Devotion of Suspect X makes an early reveal of the truth behind the murder, choosing instead to dwell on the motive not of the murder, but of its cover-up. It’s a cleverly lateral approach, and despite being thick with flashbacks (not all of them truthful) and rife with mathematical theorizing, the film never becomes confusing. On the contrary, while Alec Su’s direction is remarkably steady and engaging throughout, it also lacks a bit of a challenge for the the active spectator, watering down its maths and laying out the twists and turns of its plot with ample explanations. Like a sudoku with only 10 blank squares, it pleases the mind but doesn’t galvanize it.

Wang Kai is a charismatic and believably brilliant hero, but he is so thinly-defined that being impossibly handsome is his most salient feature. Zhang Luyi has the most ambiguous and fleshed-out role, and is at first quite efficient in his portrayal of a dried-out human being, but as the story progresses and emotion and menace becomes vital components of the character, his one-note hangdog expression and almost comical wailing in a pivotal scene are close to undermining the film’s dramatic pull. It is Ruby Lin who provides the film with a heart, in a career-best performance of touching vulnerability, quiet sympathy and a very realistic sense of determination not devoid of fear. Michiru Oshima’s score is both classy and affecting, a balance the film itself only sporadically strikes.

Long Story Short: The Devotion of Suspect X is a solid and sometimes affecting detective story that too often waters down what could have been an entertaining challenge for the mind. ***