The Devotion of Suspect X is a 2017 Chinese film based on a 2006 Japanese novel of the same name. I read a lot of mysteries, and find the structure of Japanese novels intriguing, so I was excited to watch this, having read the novel several years ago. The setting for this novel is very transferable and could even be set in the US or Europe. As an example of murder mysteries it is unusual in that we watch the murder happen and know who did it and why, and generally don't feel sorry for the victim. The rest of the film is watching the police detective and a colleague try to piece together the puzzle. The ending isn't particularily satisfiying, but it makes a subtle point about loneliness and how everyone needs connections. I teach an elective class about mysteries and detectives, and this film would be a good comparison to other "who did it" mysteries.
Spoiler Alert - the rest of my evaluation gives away the plot.
Several questions are raised by this film. A gambling-addicted ex-husband shows up at his ex-wife's door, demands money, tries to rape her and beat their teenage daughter. The daughter stuns him with a trophy and the wife manages to strangle him with a cord. How is this not clear self-defense? We had already heard other characters talk about how bad the ex-husband was, and both mother and daughter have scratches and bruises. I'm curious if the standard for self-defense are different in Japan and/or China. The neighbor, a shy, reclusive math genius, helps the wife dispose of the body and arrange an alibi. It's not clear why someone who was so clearly a genius in college is teaching junior high math, and not seeming to enjoy it. I would have liked more of his background. American audiences may find the pace very, very slow, until the big reveal at the end, and also wonder why no one questions the ex-wife's motives.
At the end, we realize the mathmatician was going to commit suicide but stopped when his new neighbors, the woman and her daughter, stopped by to introduce themselves. We see his growing, but very appropriate attraction to her, and hints that it's mutual. I kept screaming for him to just ask her out, so they could all be happy. The consequences of loneliness, and probably some mental health issues, would make this an interesting film to discuss.