Or, "容疑者Xの献身" in the original. The book, a murder mystery, is part of a series by Keigo Higashigo. It's fairly recent and due to be turned into a movie. Compared to Reason it is a significantly easier read, and the book is shorter as well, so it should be reasonably quick. On the other hand, as it is easier I have time to really make sure I do understand everything so it may not be that much faster overall. I started it on the 1st of December and have read the first chapter. I thought I'd summarize each chapter here as I finish them. If you intend to read the book and don't want to know the plot it may be a good idea to skip these posts in the future.
Our tale starts with Tetsuya Ishigami, teacher in mathematics, on his way to work in a Tokyo school. He is sharp-eyed and friendly, as evidenced by his reflecitions on the people he meets during his walk. On the way, he stops by the Bentencho lunch-box takeout place. This is not strictly because he needs lunch, but because of his secret crush on the shop assistant..
..Yasuko Hanaoka, divorcee and former bar hostess. She left hostessing for a shop assistant job when her daughter Misato was getting old enough to start school. When shop owner Sayoko Yonezawa points out that the teacher guy seems to have a crush on her and knows which days she comes to work, Yasuko freaks out. She has no favourable impression of the middle-aged and chubby Ishigami and worries he may be stalking her. The reason for her distrust soon becomes clear as the shop gets a visit from her estranged former husband..
..Shinji Toshige, smooth-talking former car salesman; you can practically hear the oily hair and too-sharp suit in the text. He swept her off her feet when they first met at a bar; they married, had Misato and Yasuko quit working. But soon Toshige was fired for embezzlement and he settled on a life of drinking and gambling while Yasuko returns to bar hostessing to earn money, money which he promptly takes from her. Tired of the abuse she finally files for divorce, but he continues to stalk her and her daughter and demanding money until she quits her job and moves away to start over at the lunch-box restaurant. I don't think we're supposed to like this guy very much.
He insists that they get together again for unstated reasons and he threatens to catch Misato at her school if Yasuko doesn't agree to meet him after work. He sneers, he even laughs evilly. She meets him after work and refuses his advances. Once she gets home, however, it turns out he's followed her. He forces himself in, smokes against her wish, makes a general nuisance of himself, and pockets some of her money almost absentmindedly. Really, all the guy needs is a goatee and a cape and the character is complete.
As Misato comes home he is naturally a complete bastard towards her as well. As she flees into another room, he follows her briefly then returns and starts to leave. As he bends to put on his shoes Misato shows up - and swings a heavy copper vase at the back of his head, felling him like an ox. Is he hurt? Is he dead? Is he going to be not happy at all about this? Ah, but that will be made clear in the next chapter...