This kind of arrangement makes browsing a bit difficult. For writers to have a chance of attracting the attention of readers just looking at the shelves, it must be much more important than in Europe to have the right publisher. In the afterword to 配達 あかずきん (Haitatsu akazukin, Delivery Red Riding Hood, 2006) by 大崎梢 (OOSAKI Kozue), the editor 戸川 安宣 (TOGAWA Yasunobu) writes that the genre 新本格 (shinhonkaku, "new orthodox detective stories") is particularly associated with Kodansha, while Tokyo Sougensha is the leader in 日常の謎 (Nichijou no nazo, "puzzles of everyday life"). As the name suggests, these are mysteries involving either a fairly minor crime or no crime at all. The Japanese seem to be the first to give the genre a name; but the thing itself has been around for a while. If you count Kleist's Der zerbrochne Krug (1808), you could say that it's older than the detective story. (The play could also be called the first courtroom drama mystery and the first appearance of the "least likely culprit", at least formally.) I remember someone mentioning Asimov's "Black Widowers" stories in this context; they are a good example of the kind of minor or non criminal puzzle characteristic of the form. It's sometimes said that the Golden Age of detective stories marked a concentration on only murder, unlike the Sherlock Holmes stories and other works of the period, which had included a variety of crimes and even mysteries without a crime. This is perhaps more a move to novels away from short stories. The short stories that Dorothy Sayers and Agatha Christie wrote also feature several crime free mysteries.
配達 あかずきん is a collection of five short stories set in what sounds like a mid sized bookshop in the shopping centre attached to a station. The main characters are full time shop assistant 杏子 (Kyouko), and part timer 多絵 (Tae). Kyouko is an industrious and capable bookseller in her mid twenties, Tae is a few years younger, a law student. They do have surnames, I think; but they are hardly ever used. Mostly they are just Kyouko and Tae, or in conversation Kyouko-san and Tae-chan (because of status, I suppose). Kyouko is always our point of view in the stories, Tae is the detective. The 'cases' generally start as non criminal problems; but a couple of stories in the collection do involve actual crimes, even one quite serious crime. For the most part, though, they take an aspect of bookshop life and use it as a little mystery. In the first story, a customer brings a friend's incomprehensible book order. Finding what he was asking for becomes an exercise in code breaking. In the second, a woman is looking for her mother, who went missing after hearing some children discussing the Genji Monogatari manga in the bookshop. In the third, the magazine the shop delivers to a nearby hairdresser has had an insulting stolen photograph of a customer inserted in it. In the fourth a women is looking for the shop assistant who advised her mother with suggestions for books for her when she was in hospital; but no-one fitting the description works at the shop. In the last, the display for a popular shounen manga is vandalised, perhaps in connexion with accusations on the internet that the work was plagiarised from an earlier doujinshi.
I like the idea of mysteries without a major crime; and I'll certainly read more in the genre. The cases here didn't include any compellingly brilliant deductions; but they are recognisably still mysteries. The emphasis is on a depiction of life behind the scenes of a bookshop. The stories are slightly humorous, slightly sentimental.