I like this cute cover!
The book opens with Gaitou Interview ("Street Interview"), which offers a seemingly harmless mystery: Kirito is approached by classmate Fujiwara, who needs some help, and Kirito is known for having a very keen eye for details. Fujiwara's sister was recently interviewed on the street about a few topics, like the trend of younger people not reading newspapers anymore. Her sister thought the interview went well, but after it was broadcast, people on the internet started bashing her sister for giving stupid answers, and some even just bad-mouthed her appearance. Fujiwara doesn't know what Kirito can do, but hopes he can somehow make it stop. After a careful examination of the street interview video, Kirito is however indeed able to miraculously stop the bashing. This is a unique kind of mystery, as it doesn't involve any real crime, but it is set-up in a convincing manner, even if some of the clues are introduced too close to Kirito's proposed solution to resolving this matter. It's a mystery you could imagine happen in real-life, and I really like how the story eventually wraps back to Kirito's own backstory of how he became known at school as a kind of detective.
Kaeru-Goroshi ("The Murder of a Frog") is about the comedy duo Frogs in the Well, consisting of Shougo and Mitsunori. Shougo is introduced to Miki, a great fan of the duo, via a mutual friend, and the two start seeing each other more often, eventually leading to them dating officially. While the two comedians have been working hard on their act, they never had their big break, until they finally manage to win first place in a prestigious comedy contest, which results in them getting more offers for appearances on television. The two are not used to their new succes, getting drained by the constant stream of gigs and to make things worse, Shougo is suddenly rejected by Miki, who, despite still being fond of him, somehow can't stand being with him anymore. It's during this period a comedian from the same agency, who has been in the trade for a very long time without any succes, finally wins his first contest. Masuoka Hideki never had much success, but he was always super nice to his juniors at the agency, so everyone is beyond happy for him, and they all gather at the offices of the agency to celebrate his long-awaited award. They all have something to drink and after a while, people walk in and out the room to make phone calls and smoke, but when Mitsunori goes out on the balcony on the third floor, he spots a dead Masuoka on the street below, and lying next to him, is a squished frog. Considering Masuoka just won an award and had his big break that very night, it doesn't seem likely this is a suicide, and suspicion falls on all who were in the building at the moment, but because it is not clear at first when Masuoka left the room and died, it is difficult to establish who was where when, and therefore who has an alibi or not. After reading the first story, I had mistakenly assumed this book would not feature murders at all, so this was a pleasant (?) surprise. Mamon spins a very Queen-esque whodunnit tale, where you use the various physical clues sprinkled across the tale to cross out suspects off the list, and there are some clever twists hidden in this process too, but what is the most memorable about this story, is definitely the motive for the murder. While a motive is a very subjective thing (one can find a motive satisfying, while someone else not at all), I find Mamon's efforts in presenting this aspect too as a fair-play mystery, and the way he set-up the motive with foreshadowing quite memorable. Considering how the whodunnit-part clewing went and the way the motive was so thoroughly foreshadowed, I can easily imagine this same short (very short!) story be fleshed out into a full novel, and it would've worked as well.
Tsuisou no Ie ("The House of Memories") is a very short story, where a father and his two adult children visit the home of the grandfather, who recently passed away. While going through his stuff, the narrator realizes something odd's going on: he has vivid memories of visiting his grandpa's study, which had bookcases filled completely with books. He hadn't visited his grandfather at home for many years, especially not because they had a fight a few years ago, but he knows his grandfather kept on buying books and that he never ever sold his books... But where have all the books his grandfather had bought after he last visited him, have gone to, as the bookcases in the study were already completely full back then? Cute little mystery that may have a very simple solution, but it just works very well with the theme of childhood memories.
Hayami Shirou wo Oikakete ("Chasing after Hayami Shirou") is a two-party mystery, where the narrator first tells how his classmate Hayami Shirou once saved him from a false accussation at school: trash had been thrown around the pool, and because the narrator had a fight with the teacher of the swimming club at the time, he was accused of the vandal act. Hayami however very ingeniously, and swiftly proves who the real culprit was. The narrator and Hayami now go to the same high school, and Hayami's talents are once again needed, when the football (soccer) club find their storeroom ransacked, with balls and other equipment stolen. The stolen items however are found the following day, having been left somewhere on the school grounds. The way Hayami deduces who the culprit is, and why, is clever and I do like the clues are based on physical senses that usually aren't featured as strongly in written fiction, though at the same time, that is also why the story kinda falls flat for me, as we read a lot about these senses, but while your mileage may vary, I did find it hard to believe how "exactly" for example a character could recognize a lingering smell. I do like the little twist at the end of the deduction process that allowed Hayami to point at the one and only culprit, and the motive works well in this school setting too.
Lunatic Retriever is set at a college mixed dormitory, which has one 'famous' inhabitant: Yoshida Haruka won a literary award at age 20 and has been publishing books these last two years. She's also quite arrogant and doesn't mingle much with the other students living in the dorm. However, that doesn't mean her death isn't a shock. On the day a solar eclipse happens, she is found dead in a storeroom inside the dorm. The storeroom was originally a smoking area inside the common room, with two doors (one opening in, the other door opening out). Before the eclipse, people tried going to the storeroom to get something, but found both doors locked for some reason. After the eclipse, the students find it odd the doors are still closed, so they force the doors open. They not only learn the doors were "locked" because they had been taped tight with duct tape, they also find a dead Haruka lying on the floor, as well as a burning stove. The room being taped shut and the burning stove suggests Haruka committed suicide by carbon monoxide poisoning, but on the other hand, they also are of the opinion Haruka would be the last person to commit suicide. But if it was murder, how did the murderer escape the taped storeroom? This is a very dense story, with a lot to offer: a taped locked room, Ellery Queen style deductions to determine who the murderer is, and we even have a solar eclipse... Because of the clue density, we even have room for multiple people presenting their theories, and interestingly, I think that in terms of the locked room mystery, the final solution isn't even as impressive as the earlier ones. What is really memorable about this story however, is the ending, when we are confronted with what is thematically an absurdly shocking revelation. It is a funny, meta-level observation that in a different work could have catastrophic implications, but it works in this short story setting and gives you some food for thought regarding the mystery genre, while also still functioning as a mystery story itself. The theme, in hindsight, can be found in other stories in the volume too, which wraps things up nicely.This is the first time I read anything by Mamon Kouhei, and while I am generally more a fan of short stories, and I did enjoy the short stories found here, I have to admit they left me wanting for more, for stories that show the same type of plotting, clewing and ways in identifying whodunnit, but with more room for depth and that is also the case for the motives, there are some really originaly character motivations at display here that result in interesting mystery settings, and I'd love to see Mamon for example trying to do a longer detective novel with such themes. So I'll keep an eye out for Mamon's future output!