Authors of mystery fiction often have certain tropes that are often found in their work. Many of them are about plotting techniques. John Dickson Carr is often associated with locked room murders and other impossible murders, while you're likely to find Queenian reasonings in the stories written by writers like Alice Arisugawa. It's often such tropes that actually attract readers to certain writers, as they know what they can expect from a certain book or writer. Another type of recurring tropes are not the actually plotting techniques, but story-related themes. Some might like to involve romantic subplots for example, or have their stories set in a certain place and time. Ashibe Taku is one of those writers who has a very distinct set of such story themes that you're likely to find in any randomly selected story by him and vice-versa, once you have read a few of his stories you'll immediately know the themes he likes to write about in his mystery stories. The easiest themes to identify are the literary and historical references in his stories. As far as I know, Murder in the Red Chamber is the only full-length novel by Ashibe available in English at the moment, but that too is an excellent example of his themes, as the book is based on the Chinese 18th century classic Dream of the Red Chamber, and naturally full of references to both the literary work itself, as well as historical references and research. The historical and literary references are naturally also found in his pastiche series The Exhibition of Great Detectives (1 and 2), which features crossovers between famous fictional detective, but even a book like Wadokei no Yakata no Satsujin ("The Japanese Clock Mansion Murders", 2000), set in modern times, will show off the literary and historical research does for his books. A third common trope in Ashibe's work is the city of Osaka, to be exact, the old Osaka, not the metropolis it has become now, but the old commercial modern city it became after the industrial revolution and that is now slowly disappearing as the current Osaka is becoming more like a gigantic metropolis like Tokyo. In works like Satsujin Kigeki no Modern City ("A Murder Comedy In The Modern City", 1994) he explores a bustling 1920s Osaka, while in Toki no Misshitsu ("A Locked Space in Time", 2001). he explores the change of Osaka by having his series detective Morie Shunsaku tackle two case, one set in the Osaka of 2001 and one set in the Osaka of the nineteenth century. One can easily sense Ashibe's love for the old Osaka in all of his works.
Oomarike Satsujin Jiken starts with a short prologue set in 1906, when young Oomari Sentarou disappears mysteriously during a visit to the Panorama near Osaka's Namba Station. The disappearance of Sentarou, the heir of Oomari Pharmacy, was perhaps a sign to the immenent decay of the once well-known family of merchants. Decades ago, Oomari Pharmacy was a household name in Osaka when it came to medicine, but recently, they had moved to selling make-up too, which was a brilliant business move. The Oomari family lived in Semba, the commercial centre of Osaka, brimming with other merchants and their apprentices. Sentarou was never found, and years later, his sister Kiyoe and her husband Shigezou became the new heads of the family, leading the Oomaris during dangerous times. For over thirty years after Sentarou's disappearance, World War II would begin and eventually, Japan would involve themselves in the war too. It's during this time the decline of Oomari Pharmacy starts: importing make-up had slowly become impossible and the act of selling make-up itself was deemed a very anti-nationalistic deed, so it didn't take long for Oomari Pharmacy to get into financial problems. Once a name known throughout the city, by the time the war was in full swing, Oomari Pharmacy had only one real apprentice (a so-called "Decchi") left in the shop, where all they could do was sell amenity kits for soldiers. What was even more worrying was that the future of the Oomari family itself was uncertain. Second son Shigehiko, who was suppose to take the company over, had been drafted and sent away to the battlefield already, while oldest son Taiichirou, a doctor, had been drafted too as an army doctor. Taichirou's wife Mineko decides to move to the Oomari home during the war while awaiting her husband, where she gets badly along with sister-in-law Tsukiko, and very well along with her young sister-in-law Fumiko. All they can do is hold the fort until the war is over and Taichirou and Shigehiko return, but it is in 1945, in the last months of the war, that disaster strikes at the Oomari home. After an attack on Tsukiko, the body of patriarch Shigezou is found in his room, hanging from the ceiling. While it doesn't seem like anyone would have a reason to kill him, there are clear signs that indicate this wasn't a suicide or accident, but as times passes by, more members of the family are killed in gruesome manners. Meanwhile, Mineko, as the wife of the oldest son, finds herself being pushed into the role of the one carrying the family, but luckily she finds that her old classmate, Nishi Natsuko, is a training as a doctor at the local doctor, and she turns out to be a powerful ally as they both try to figure out who is killing the members of the Oomari family and why.
While the book opens with a very Rampo-esque trope (the visit to the Panorama), who was a very Tokyo-focused writer, Oomarike Satsujin Jiken quickly becomes a tale that focuses truly on the old Osaka that doesn't exist anymore: the traditional commercial district of Semba really comes alive in the pages of this book, with most characters speaking in the old Semba-dialect, utilizing a lot of local culture like the decchi apprenticeships in the plot, highlighting a lot of the cultural, social and economic changes as World War II starts to near its conclusion. Literary references are also plenty abound, though most of them are specially about mystery literature, as both Shigehiko and his young sister Fumiko are fans of mystery fiction and we see a lot of works of mystery mentioned, often with their old translation titles that aren't in use anymore nowadays. The tone the book takes betrays Ashibe's deep anti-war sentiments and makes the tale of the slow, but certain fall of the Oomari family even more tragic. Oomarike Satsujin Jiken is a mystery novel foremost, but it does a great job at presenting a "historical, war-time Osaka" novel, a theme Ashibe loves, and at least for me, the book had enough themes and topics I had never heard about that really made this an educational, and interesting read. Whereas historical or literary references in other Ashibe stories sometimes feel too much like references "by a fan, for fans", making them not as accessible to the general public, I think the focus on the fall of the Oomaris during the war and using the old Osaka as its backdrop works great, giving the book a much wider appeal (which might explain why it won the earlier mentioned awards).
You don't really have "fancy" murders here, no locked room murders or mysteries that are solved through lengthy Queenian chains of deduction, but Ashibe manages to make each of the murders really feel like they could only have been executed as such in the time and place showcased in the book. And while this does mean some historical knowledge is required to really solve the mysteries yourself, all the clues are brilliantly hidden within the narrative, which is what makes Oomarike Satsujin Jiken a very satisfying read. What really makes this a memorable mystery story though is the motive of the murderer both in the broad and narrow sense of the word. By which I mean, the murderer's motive is only understandable considering the historical time/location of this book, but also the reason why the murderer chose to commit each murder in a particular way, is only understandable given that historical context. All the murders might seem a bit underwhelming taken seperately, and might even seen nonsensical at times if you just take them as is, but they make so much more sense and convincing when explained through the historical background, resulting in a motive that is truly unique to the Oomari family in Semba in the 1940, and murders that are commited in a way that is also unique to the 1940s Semba setting. I’d say the balance between the mystery plot and the common Ashibe tropes is done better than in a lot of Ashibe's other works (not going too far into a specific field), and it's this balance, and the synergy between these themes that make this book the best "Ashibe-esque" mystery novel he has written.
Oh, and just a little bit of trivia, but a somewhat curious amateur detective called Houjou Koushirou appears early on in Oomarike Satsujin Jiken, who will make a lot of readers think of Kindaichi Kousuke: this character is actually named after mystery author Houjou Kie! The book also has a lot of little references to other characters (series) by Ashibe. though I only caught a few of them (like Osaka-bred Tsuruko from the Modern City series), so in that perspective, there's still a lot in this book only long-time Ashibe readers will notice.
So as someone who has read quite a few books written by Ashibe Taku and enjoyed most of them too, I think Oomarike Satsujin Jiken might be the book where he managed to combine all his personal tropes and the mystery plot the best. It is undoubtedly a work that could only have written by him, addressing all the specific themes he likes, and he uses those themes to tell a gripping mystery story set during World War II that really comes alive because of the historical setting. I think a lot of people who like the Yokomizo novels for their historical context, but aren't too big a fan of the grotesque, will probably like this novel a lot too, as it does address similar themes like the decline of a family along generations and the effects of the war on society.
