I always think of white and blue when I think of the covers for the Koigakubo Academy books, even those are not even the primary colors for every cover...
Disclosure: I translated Higashigawa Tokuya's Lending the Key to the Locked Room. If you haven't read it yet... read it!
Higashigawa Tokuya first introduced his readers to the fictional school of Koigakubo Academy, located in Kokubunji, Tokyo, in 2002 with Manabanai Tantei-tachi no Gakuen. In that book, we followed the members of the Koigakubo Academy Detective Club as they tackled a murder case that happened at school. After the first book about the Detective Club, we have seen other books featuring the Detective Club too, but interestingly enough, Higashigawa also started to feature the high school in other books that weren't about the Detective Club exclusively. First we had the Kirigamine Ryou series, which featured the vice-president of the Detective Club who for some reason very seldomly met the characters of the main series, but still often came across mysteries herself. Four years ago, Higashigawa wrote Kimi ni Yomasetai Mystery ga Arunda, a wonderful short story collection about the Second Literature Club of Koigakubo Academy. And 2024, the twentieth anniversary since the first book with the Koigakubo Academy, brought us another new series about the school where so many odd happenings happen, both criminal and not. The binding element between all these series is the school itself, with some characters like the teachers or a delinquent student appearing in several series, while usually the main characters of each series remains in their own 'part' of the world.
The first tale, Meitantei, Misshitsu ni Arawaru ("The Great Detective Appears in the Locked Room"), introduces us to the main characters of Asahina, Mamory and Wataru, and also shows a bit of Koigakubo Academy's Mystery Club, which we have seen previously in the second Kirigamine Ryou short story collection. The problem involves a theft from a club room: the club members all saw how the manuscript was left in a locker in the room and they left the room together, saw how the padlock was put on the door and one of them returned the key to the teacher in charge. The key is specially made and can't be copied, and the teachers keep club room keys in a room with camera surveillance, so it appears only Mamoru, who took the key the following day, could've stolen the manuscript in the morning. Asahina presents a few fairly simple theories which are discarded fairly easily, which is perhaps also why the actual solution to the conundrum is also fairly simply: this solution is basically of the same level Asahina could and should have presented herself, and should've been shot down too. So to have the mysterious Wataru appear only to point out a simple solution....
Satsujin ga Misui Datta Hanashi ("A Story About an Attempt at Murder") starts with Asahina hearing the shocking news a student of Koigakubo Academy had been assaulted the previous night. The girl had been to a concert of Tamaranzaka 24 and had been on her way home, crossing a grove near the station, when she was attacked and stabbed in her stomach. She was found by a classmate who quickly called the emergency line. Because the girl's a classmate of Mamoru, Asahina decides to use him as her Watson to learn more about the case. They visit the mother of the victim, and learn the daughter didn't quite get along with the mother's boyfriend, but he has an alibi for when the girl was assaulted. While the actual truth behind why the girl was attacked is not very surprising or original on its own, I love the deduction chain Higashigawa laid out for the reader. The clue that leads to the revelation of how it was done is really good, and expertly hidden, and easily one of my favorite clues of the whole book.
Asahina Reika is the honorary student council president, which means she supervises the board meetings once in a while (when she feels like it), and the other members just have to dance to her tune. the day after another meeting, Asahina visits the board office to use her locker there, when she notices a window was left open. She then realizes someone has moved some of her books in her locker, so she summons Mamoru (and Wataru) to help her find the insolent person who dares go through her stuff in Seitokaiyakuinshitsu no Koubou ("Offence and Defence in the Student Board Office"). After a good slap, we see Wataru's observations of a few clues that ultimately lead Asahina and Wataru to a rather surprising discovery, which shows there was something far more sinister going on in the student board office than just a theft. Not a huge fan of the story to be honest: the first half the mystery-solving is more focused on reverse-engineering Wataru's deductions about the intruder's actions, rather than doing that ourselves and in the second half, we investigate a mysterious message that... probably would have been more interesting in a visual medium, but not in a prose form.
Tenshi wa Poolside ni Ukabu ("Angels Floating at the Poolside") is set during a summer evening: students are still around at school because of two events: geography teacher Ikegami is supervising a group to watch the stars (she herself is actually a huge believer of UFOs), while another group of students are playing night baseball on the school grounds. A guard meanwhile is making his rounds, when he senses something's wrong with the school's pool. While the fence is properly locked and barbed wire ensures nobody can climb inside (or as some swimming club members say, it's to prevent members from fleeing training), the guard still can't shake the feeling someone is inside, so he unlocks the pool gate and has a look around. His attention is drawn to one of the diving boards, so he climbs the ladder. He's nearly at the top when he suddenly feels something hard hit his head, and he falls of the ladder, hits his head on the ground and is knocked out. But just before he passes out, he's sure he saw a winged angel flying in the sky above him... The guard is later found by students passing by. Asahina of course can't help herself and decides to investigate herself (with Mamoru/Wataru as her Watson). This is another story where I think it would've been better had it been created in a visual medium. While I think the solution on its own is okay, I think asking the reader to deduce it based on the hints is a bit too much, while it would've been much more natural if the story had been told in a visual format. The attack on the guard (which is kinda impossible because he was hit on the head while climbing up the ladder and he didn't see anyone on the diving board before he was knocked out) is connected well to the guard seeing floating angels, but it's still a story that has trouble feeling really satisfying.
The final story, Chashitsu ni Kieta Shoujo ("The Girl Who Disappeared In the Tea-Ceremony Room"), has Asahina wondering whether he should tell Mamoru about Wataru taking his body over each time he's hit on the head, but before she can make a decision, she and Mamoru stumble upon a new case, and a very personal one too: Asahina sees a brown-haired girl rummaging through her desk in the classroom! Asahina and Mamoru give chase, and they eventually find the girl running into a remote part of the campus, which is walled off and ends in a cul-de-sac where the tea-ceremony room is, a small building used by the tea ceremony club. Mamoru is sent inside the room by Asahina, but it appears there's only a tea ceremony club member inside, who is far too tall to be the girl Asahina saw. A swift look across the room also shows there's no place for the brown-haired girl to hide inside. Asahina then decides to check behind the tea-ceremony room too (she makes sure Mamoru goes the other way around the building), but they only find a delinquent student trying to smoke in secret. But as this part of the campus is completely walled-off, how did the girl escape if she's not in the tea-ceremony room nor behind it? Impossible disappearances are pretty much a staple of the mysteries set at Koigakubo Academy, as other books also feature them (especially the Kirigamine Ryou series), and even with that in mind, I'd say this is a pretty good story. The solution is very simple, but also quite clever: it would have been pretty interesting on its own as it makes good use of the unusual setting, but Higashigawa manages to tie a very unique clue to it too, giving it another level of depth. Just don't come here expecting some real resolution regarding the Mamoru/Wataru plotline.
Overall though, I'll need to be honest and say that Asahina-san to Himitsu no Aibou is probably my least favorite short story collection set at Koigakubo Academy until now. I love the Kirigamine Ryou stories with the overly-enthusiastic Kirigamine and the weird disappearances and other impossible crimes(?) she encounters, and I was really surprised by how fantastically Kimi ni Yomasetai Mystery ga Arunda was set-up with multiple meta-level stories, but in comparison, the plots of Asahina-san to Himitsu no Aibou seemed a lot simpler, with less finesse going on in regards to how the mysteries were planned. And I guess I never got really invested in the Ranma 1/2 / Touch-esque subplot of Mamoru and Wataru (hmm, now I think about it, it does have a Shonen Sunday vibe to it), so that wasn't really something that kept me interested. I'm always in for more stories set at Koigakubo Academy, and it was fun seeing familiar faces pop up in the background, but I guess I did expect something more 'grand' for the twentieth anniversary of the setting. Let's hope the next one is more memorable.
