For some reason I thought the original 2020 paperback release of this book had a different cover with a more greenish tint, and the 2022 pocket release had similar, but different art with a more blueish tone, but it turns out they have the exact same cover...
The title and opening story Toumei Ningen wa Misshitsu ni Hisomu ("An Invisible Person is Lurking in the Locked Room") is inspired by H.G. Wells' The Invisible Man and tells about a worldwide disease which makes people invisible. People slowly turn completely invisible, including their bodily fluids and human waste and for the moment, No permanent cure has been found yet, and society has learned to adapt to the people with invisibility condition. Modern society generally only works if everyone is visible, for even doing groceries or walking down the street can be difficult if people can't see you and constantly walk into you, so invisible people are expected to either use make-up to become visible, or take daily inhibitor pills that turn them visible again, The story starts with narration by an invisible married woman, who one day learns a professor at a nearby university is close to producing a permanent cure to the invisibility disease. The woman decides she needs to kill the professor and destroy his research, and plans his murder: her plan involves parking near the university, undress completely and in her invisible state, sneak inside the lab offices and kill the professor. She meticulously plans her deed, plotting which route to take so she won't bump into people, stop taking her inhibitor pills early in the week so she becomes invsible again, but masking that fact by wearing make-up and even making sure to have an easy to digest breakfast, as until the food is digested, you'd see food flying around. The woman manages to slip in the lab and indeed kills the professor, but then loud cries come from the other side of the door. At that moment, we switch to the viewpoint of the husband, who first thought his wife might be cheating on him and hired a private detective to trail her, and eventually, the two realized the woman was planning to kill the professor. They arrived at the lab just after the murder occured, and together with two students, they enter the room and immediately lock it behind them, for they know the murderer, the invisible murderer must still be inside the room. And thus starts a game of cat and mouse, where the four men try to catch the invisible murderer hiding in the lab, while our murderer knows that if she manages to escape this locked room, they can never prove she killed the professor.
An incredibly fun premise and it's almost a shame this is a short story, because there is a lot of potential for more! Because of the relatively short length of the tale, the game of cat and mouse is over pretty soon, but it's a fun one: the four men know the murderer is somewhere in the room as the professor is dead and nobody had opened the door since he was last seen alive by his students, but it's a pretty spacious lab with desks for the various students, so how are they going to find an invisible person here? They try all kinds of things to search the spacious room, but also have to be careful she doesn't attack them suddenly in an attempt to escape. Meanwhile, the invisible woman has staked all her bets on one attempt to escape this room, and it's a pretty daring one and while after a while, you probably start to guess what she's doing, it's a perfectly well-clewed solution to her situation. But it's all over rather soon, and you just wish Atsukawa had done more with the idea of the invisibility disease. Perhaps as a follow-up novel?
Rokunin no Nekkyou Suru Nihonjin ("Six Enthusiastic Japanese") is inspired by Mitani Kouki's play 12nin no Yasashii Nihonjin ("Twelve Gentle Japanese"), itself a parody of the film Twelve Angry Men. In Twelve Angry Men, we had jury members in a murder trial who were immediately convinced of the defendant's guilt, 12nin no Yasashii Nihonjin started with the jury members all being convinced the defendant is not guilty, so what is this story about? The narrator is a professional judge, who together with two other professional judges and six lay judges are deliberating over a murder trial. The defendant and victim were both fans of the idol group Cutie Girls, and they had been travelling together to attend to a two-day event of Cutie Girls. The victim had been murdered in their room at an inn, apparently they were watching a DVD of Cutie Girls together when they started arguing resulting in an unfortunate lethal blow. Initially, most lay judges seem to agree the defendant is guilty as he has confessed to the crime, but one isn't convinced, and as he starts zooming in on all kinds of facts at the crime scene, the others are slowly won over and together, they arrive at a rather surprising solution... This story is really funny, and definitely intended as a kind of parody. The crime scene is rather unique in that the story utilizes a lot of "idol otaku props", like glow sticks, idol calls and more, and you get surprisingly deep deduction chains about something like the proper way to store a glow stick. The big climax of the story is really something you have to behold, and while I think that the individual deductions are not super memorable, the "punchline" of this story definitely is.
Touchou Sareta Satsujin ("The Tapped Murder") introduces us to Mimika, a young woman who works at a detective agency and who has superior powers of hearing, being able to make out the smallest of noises. But that's all she can do however, so usually, it is her boss who has to make the connections based on the evidence Mimika heard. Their current case however, is special. For the last week, they had been investigating Kunisaki Chiharu, whose husband suspected she was cheating on him. With the help of the husband, they planted a teddy bear with a sound recorder inside it in the sitting room, but one day Chiharu was killed in the sitting room. When the teddy bear was discovered, the detective agency of course became a momentary target of investigation by the police, so now Mimika's boss wants Mimika to help clear their name. The teddy bear had indeed recorded the moment of the actual murder, and while listening to the audio file, Mimika hears a faint dissonant tone, but she can't figure out what the noise exactly is. Because they know the husband himself was actually also cheating on his wife himself, they suspect he might be the murderer, and they come up with an excuse to visit the apartment and the crime scene again, with Mimika trying to figure out what the dissonant tone was she heard during the murder and whether it can help them solve this case. This is a story that I really would have wanted to experience as an audio drama! The mystery of the dissonant tone and other hidden "audio" clues in the audio file are all fairly clever, though I do think more clues pointing directly to the murderer would've been nice, but reading about these clues you were supposed to hear does make it feel a bit less impressive than I think it should be. Definitely a fun take for a mystery story though. In fact, it's a shame you don't really have "direct-to-audio" mystery fiction...
Dai 13-gou Senshitsu Kara no Dasshutsu ("Escape from Cabin 13") is inspired by Jacques Futrelle's The Problem of Cell 13, but with a very modern twist: escape rooms! Kaito is a high school student who is attending a special invitation-only preview of an escape room event of the popular series Great Detective Sakuragi. The murder game event is held on a ship and has the participants solve a series of puzzles which will eventually lead them to the identity of the murderer. At the event, Kaito runs into his classmate Masaru, with whom he has a kind of a rivalry going. Masaru and his younger brother Suguru are sons of a wealthy family who happen to be sponsoring this event, which landed them the special invitations. During the game however, Kaito and Suguru are abducted by men dressed as sailors and held captive in Cabin 13, while for some reason Masaru keeps on playing the escape room game. Why were Kaito and Suguru captured, can they escape their predicement and why is Masaru still playing the game? I believe this is the longest story in the collection, and it is pretty "busy": we have Kaito and Suguru trying to figure out how to escape the cabin, but meanwhile Masaru is playing the escape room event as planned, so we get the four puzzles in the event to solve ourselves too. Of course, the big surprise is to see how these two plotlines eventually connect back together again, and while I do like the basic ideas behind this story, it somehow didn't quite work for me. The plot of the story is a bit reminscent of Detective Conan treasure hunts, with a few puzzles with a hidden meaning behind them, and while I like the big connection that is revealed, the actual puzzles of the escape room didn't really interest me (they are also discussed rather briefly), while the escape attempts from Cabin 13 also move rather slowly.
As mentioned in the introduction, I think Toumei Ningen wa Misshitsu ni Hisomu on the whole has some pretty good stories: three of the four I really like, and I don't really dislike the last either. But the stories are all very short, so especially the first story feels like it has an underutilized premise and because the book is so short, I also kinda hesitate recommending this in this specific form, as a short story collection. I will gladly point to the title story if I happen to be talking about invisible murderers in the future, but perhaps some of these stories will make their way into an anthology or something like that, and you might as well read them there then.