Natsuhiko Kyougoku's The Summer of the Ubume, particularly, the manga version that I've read, has a good mystery theme. However, I have a big problem with the work as a whole. Spoiler alert when reading this! Despite the rather negative nature of this review, I'd still recommend anyone who read this to read that work first, in either manga or novel format. The manga is only 4 books long at typical ~187 pages each.

Again, let me warn you of spoilers once more before continuing.

Chuzenji's Monologue™

Chuuzenji spends too much time philosophizing, which strikes me as obfuscating something, and I was right about this. Luckily, the condescending is just enough to keep me reading and not break.

To elaborate, he spends pages establishing ideas about: consciousness, perception, memory, folklore, superstition, science, quantum mechanics (not kidding here), causality, and how humans construct explanations. On the surface, this is thematic groundwork. But retrospectively, a lot of it functions as mystery camouflage.

The author tells me to:

"Pay attention to the philosophical problem of how humans perceive reality,"

while the actual mystery is eventually:

"Several people have crap memories and at least three of them didn't notice a corpse in a room, in a plain sight."

To be fair, the philosophy isn't irrelevant, exactly. It establishes the conceptual language needed to explain why the characters interpret events incorrectly. However, there is a difference between making a theme relevant and using the theme to make an otherwise weak mechanism feel profound. The most suspicious part is how Chuuzenji's gushing lectures repeatedly seem to promise that I am approaching some enormous ontological revelation. Then the actual answer is much, much more mundane.

Memory is used as an overly elastic plot mechanism

The entire mystery's black box is held with cellophane tape of contrived people memories, as if the writer is saying:

"SEE! WHAT DID I TELL YOU ABOUT MEMORIES BEING BLAH BLAH BLAH AND BLAH"

A mystery can absolutely use unreliable memory. Few cases in Motohiro Katou's QED did this, such as the smart guy who killed his Santa Claus looking neighbour, or the Ponzi schemer who forgot that he's already old. And Katou did this right, as the mystery is much more simpler and doesn't involve the author doing sudo rm -rf memory-of-this-case.mem

The problem is when the solution starts depending on"

"Person A remembers X incorrectly because of Y, Person B remembers Z incorrectly because of W, and the correct memory was inaccessible until the appropriate psychological trigger occurred..."

There's zero rules and memory becomes the mystery equivalent of a universal solvent that the author uses to dissolve anything.

Natsu no Ubume asks the reader to accept very specific distortions precisely where the author needs them. And then, Chuuzenji can basically walk into the room and reconstruct the hidden configuration.

Tied to my first point, the the story spends a huge amount of effort saying:

"Human memory is unreliable!"

then also establish:

"Therefore these particular memories became distorted in exactly these particular ways."

These are two different propositions, and should not be used like: "Since A, therefore B".

The manga's visual characterization leaks suspicion

Aki Shimizu, as the artist, felt too manipulative. Ryouko is drawn beautiful, but other member of the family is drawn rather unpleasant. Seeing this discrepancy, as soon as the family is shown, I immediately pin Ryouko as the perpetrator. The artist, conscious or not, seems to draw the Kuonji household as:

"LOOK! THIS CHARACTER APPEARS BAD, ONE OF THEM MUST BE THE CULPRIT!"

That said, this non-verbal characterization where Ryouko, for nearly the entirety of the work, consistently presented as beautiful, composed, elegant, and visually distinctive, while her family is drawn otherwise, might not be Shimizu's fault. It can be conventional visual language of manga, where Ryouko is presented as "heroine". There's Acchan, but she doesn't have enough screen time and in the grand scheme, is merely flavor to the story.

On the other side, my brain also already work this way:

Beautiful mysterious woman + strange family + conspicuous visual contrast = She did it.

Enokizu is artificially prevented from collapsing the mystery

Enokizu can be cut from the story, and nothing would've changed. Okay, to be exact, he's useless to the mystery. The only thing that matters for his role is that he reports to police at once when he saw Makio's body. Police should then come, break the storage room, find the babies, and the story ends there at half the length. But no, AUTHOR NEED TO ORGASM BY WRITING MORE OF CHUUZENJI'S MONOLOGUE™.

By perceiving memories, Enokizu has an absurdly powerful ability in a mystery novel. And then the author doesn't allow him to function at maximum usefulness because doing so would destroy the architecture of the mystery. Gosh, let me phrase that again: A detective character prevented from solving the mystery because the plot needs him not to solve it. There should be a compelling reason intrinsic to the story other than "The author forbid it".

Which makes me wonder in Enokizu can potentially become the mechanical shortcut, why write him with this ability at all? He does serve to foreshadow the frog-headed baby, but that same explanation is covered by Tomiko (Toshizou's wife). So out of things that Enokizu can do, it's the police reporting that cuts the story's length, saving readers from Chuuzenji's Monologue™. When even the author failed to do that, he's a flavorful background character.

Chuuzenji's rationalism becomes selectively convenient.

Chuuzenji's has an inconsistent and selective stance in his belief, i.e. in what's scientific and what's esoteric. This is expected as his "power" is author's plot device. Take the "exorcism" scene: suddenly by performing the "exorcism", everyone memory came back for no apparent reason other than "magic happened", but Chuuzenji himself doesn't see it this way: he believed that he is laying words of truth that shook people and snapped them back to reality (oh there goes gravity! eeeh, we're not going there). This reveal of the mystery's black box felt so cop out, that it veered into comedy.

Someone like Chuuzenji can say "The supernatural explanation is culturally meaningful, but I don't believe the supernatural entity literally exists.", thus his "exorcism" can be understood as psychological or social intervention rather than literal magic. However, the story's causal machinery begins behaving like magic anyway: the memories somehow return, people somehow willing to divulge information that was apparently hush hush before, somehow there's a backstage perpetrator (Dr. Sugano), somehow somehow somehow.

If the story established a credible psychological mechanism by which Chuuzenji's intervention causes suppressed memories to become accessible, by any esoteric means if available and Chuuzenji isn't trying to ground it as normal, then great. But what happened is that Chuzenji performs exorcism, psychological barriers collapse, everyone remembers the required information, Chuuzenji explains why this isn't magic. I reserve my right to felt narratively cheated.

Young adult twins? Incoming Wrong Twin plot

This has recently become rule: if there's twins or look-alikes in a mystery works, and they are young adults, Wrong Twin protocol must be active. I do need to underline that Ryouko and Kyouko are not twins, they are sisters who has few years of age gap. However, the effect remains same. Once the narrative say that Ryouko and Kyouko looks remarkably alike, I don't even need additional clues that Sekiguchi met the wrong twin.

The work spent few hundred pages discussing epistemology, memory, folklore, pregnancy, consciousness, perception and the ontological status of supernatural phenomena, and here I am thinking:

"It's gonna be wrong twin, right?"

then boom, there it is, at Book 4.

Conclusion

Sometimes reading too much mystery can spoil the mystery, but that doesn't mean I'll read less mystery. And I'm still gonna read Mouryou no Hako.