Always happy when "an out-of-print book I'm eyeing, but won't buy because a used copy is too expensive" is re-released!
My first encounter with Ooyama Seiichirou was via the PSP game Trick X Logic, and since that occasion, I've been a fan of his puzzle plot short stories, which range from a locked room short story collection with a unique Ellery Queen-style logic focus, to his cracking alibi-cracking stories and a fun collection where you never know who the main detective is, only the Watson, but you might have noticed one thing here: Ooyama specializes in short stories. In fact, Kamen Gensoukyoku is still the only full-length novel he has published at this moment. I had been wanting to read this for a while because I am a fan of his writings, but the original release wasn't really cheap on the used market, so I had been postponing it for a long while. Last year however, at the start of 2022, Ooyama wrote on Twitter he was working on the manuscript of the book to get it ready for a pocket re-release, which really made me enthusiastic... and then the year passed, and at the start of 2023, Ooyama tweeted once again he was (still) working on it. This was getting a bit worrisome, but fortunately, the pocket did get released in 2023, with a nifty new cover too!
I have to admit I was a bit surprised by the very Yokomizo Seishi-esque vibe of the book, being set soon after World War II, set in a rural place with a silk factory as its main economic engine, and of course a family traditions of focusing twins and family fueds playing a big role in the story. A lot of what I read by Ooyama is very contemporary, so I hadn't expected such a shift all, but that did really pique my interest. On the whole, I do think that if you like Yokomizo-style stories, you'll find a lot to like here too, though the writing style itself is contemporary, and definitely lightheartier than Yokomizo. There's of course also a distinct Carr feeling, as the plot is reminiscent of It Walks by Night.
The murder on Fumihiko occurs fairly early in the book, and because they know that a) Takehiko has secretly returned to Maibara the last few months after his visit to the brilliant plastic surgeon and has taken on a new identity, b) that Fumihiko must've been deceived by Takehiko, not knowing that one of the people whom he has become acquainted with/hired these last few months is actually his twin brother, the investigation of Keisuke and Naoko quickly turns to figuring out who of the people in Maibara could be Takehiko in disguise. Police investigation show that the plastic surgeon, Masuo, was absolutely brilliant, having his arts abroad, but he ended up in the illegal sector. While details of his records were wiped, it shows Takehiko did undergo a surgery to change his appearance, though we don't know the details. Still, because he only went facial surgery, Keisuke and Naoko of course realize Takehiko could only be disguised as someone who still resembles his original self somewhat, so being a man in the same age range (and that he's not likely to be living as an old lady now), but who could it be?
The book is fairly short, so while a few more events follow after the Fumihiko murder, including another murder and also a more thorough investigation into Sayako's death a year ago and who likely sent the poison pen letters about her, we're almost near the solution, and that's of course, as you'd expect of Ooyama, very much Queen-inspired, focusing on the actions we know the murderer=Takehiko must have taken to commit the murder on his brother to identify a few characteristics, which are then applied to the suspects to see which of them can be the murderer. There is one major trick here that is probably the one thing you'll remember about this book, and it's both quite brilliant, and a bit underplayed. The idea itself is really good: there's very clever misdirection going on regarding this that really invites you to re-read certain parts carefully to see Ooyama did indeed play very fair. It is a concept that nearly borders on concepts you'd also expect in Mitsuda's Toujou Genya books, which was perhaps why it caught me completely off-guard, because I might've expected in a Genya book, but I didn't because I was still so used to Ooyama's contemporary tales. It is a simple idea, but executed very well. At the same time though, one can also argue the trick only makes sense from a reader's point of view. One can't deny that for this trick to work, the characters of the book basically had to act in a certain way, even if it wasn't the most logical/obvious thing to do. Meaning, the trick itself is done brilliantly: but was it really necessary to do it like that? Would all the actors who are involved one way or another really always act like that? Taking a step back, the plan is a bit more convoluted than it ever needs to be for the murderer, but you know, the main trick is still memorable, and on those merits alone, I think the book's worth a read, as the biggest step on the logical road towards identifying Takehiko is really impressive in its simplicity.
If you're like me and you have read (a lot of other) Ooyama Seiichirou short stories, Kamen Gensoukyoku, will feel quite refreshingly different, despite feeling very much like a classic detective story. The set-up is not overly large in scale, but it is clear from Ooyama had one big idea as he wrote this book, which is executed in a clever manner, resulting in a satisfying mystery novel. Definitely worth picking up if you're an Ooyama fan! If you haven't read anything by him yet, this is still a fun novel, though he's mainly a short story writer, so this book is not really representative of his trademark style.