Top 19 Completed Japanese Mystery Novels in 2026

2026 Edition

Updated January 27, 2026

Specialized Lists

19 Novels

Japanese mystery traditions emphasize fair play and logical deduction more strictly than some Western counterparts. The emphasis on puzzle construction means readers can often solve cases before the reveal if they pay attention. Completion matters absolutely for mysteries since the entire genre depends on the solution.

These completed entries provide full mysteries with proper resolutions. Japanese mystery webnovels sometimes blend with supernatural or fantasy elements, creating hybrid puzzles. The finished status guarantees you'll learn whodunit.

Completed
1
TOP PICK
Kumo Desu ga, Nani ka?
4.4
(1.9K ratings)
Genre: action, adventure, comedy
The world where the Hero and the Demon King continue to oppose each other. The grand magic from the Hero and the Demon King cross over worlds and exploded in the classroom of a certain high school.
First Impressions
"Kumo Desu ga, Nani ka?" is a web novel that took me on quite the ride. It's a reincarnation story with a twist, throwing our protagonist into the body of a spider monster in a deadly labyrinth. While the initial premise might sound familiar, the execution is anything but typical. Initially, I was hooked by the unique perspective of a spider navigating a dangerous world. The early chapters focus heavily on survival, grinding, and skill acquisition. Some might find this part slow-paced, and even repetitive, but I found it quite entertaining, especially with the main character's internal monolog...
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Completed
2
RUNNER UP
Shini Yasui Kōshaku Reijō to Shichi-nin no Kikōshi
4.5
(638 ratings)
Genre: action, adventure, fantasy
On one spring evening when I was eight years old, I, Erica, Duke of Aurelia’s daughter, realized something. Huh, I have reincarnated into a fantasy world, haven’t I?
First Impressions
"Reincarnated as a villainess" stories are a dime a dozen, so I went into Shini Yasui Kōshaku Reijō to Shichi-nin no Kikōshi with a healthy dose of skepticism. However, I quickly found myself pulled in by the unique premise and the promise of more than just your typical otome game fare. The detailed world-building and hints of mystery piqued my interest from the start, and I was eager to see how Erica would navigate her perilous situation. The strongest aspect of this novel, in my opinion, is its world-building. The author has clearly put a lot of thought into the intricacies of the world, fro...
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Completed
3
HIGHLY RECOMMENDED
Fake Saint Of The Year
4.7
(695 ratings)
Genre: adventure, comedy, fantasy
Fudou Niito, a resident of Japan, went to bed dissatisfied with the ending of the game. When he next awoke, he found himself in the body of the game’s hated fake saint, Elrise.
First Impressions
"Fake Saint Of The Year" really took me by surprise. Going in, I expected a fairly standard gender-bender isekai, but what I found was a surprisingly deep and engaging story that kept me hooked until the very end. Initially, I'll admit, I wasn't entirely sold. The early chapters felt a little clumsy, and I wasn't quite connecting with the protagonist, Elrise. The world-building felt a bit rushed, and I was wondering if this would be another generic isekai. However, I'm really glad I stuck with it, because the story really takes off after the first few chapters....
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Completed
4
EDITORS CHOICE
I Favor the Villainess
4.4
(624 ratings)
Genre: comedy, drama, fantasy
“I am the heroine of an otome game, so is it wrong to like the villainess? ” Corporate s*ave OL, Oohashi Rei, reincarnated as the heroine Rei Taylor in the world of the otome game 「Revolution」.
First Impressions
"I Favor the Villainess" had me hooked from the start with its unique premise: a protagonist reincarnated into an otome game who's far more interested in wooing the villainess than any of the male leads. It's a refreshing twist on the isekai formula, and I found myself eager to see how Rei, the main character, would charm the prickly Claire. Initially, I was drawn in by the humor and the dynamic between Rei and Claire. Their interactions are genuinely funny, and the story has a light-hearted feel that makes it easy to pick up and enjoy. It felt like a fun, fluffy yuri romance with a comedic ed...
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Completed
5
EDITORS CHOICE
She Was Both Called God, as Well as Satan
4.5
(413 ratings)
Genre: adventure, fantasy, mystery
In the distant future on Earth, there was a girl with God-like powers. That girl is the last survivor of the former human race that flourished in ancient times.
First Impressions
"She Was Both Called God, as Well as Satan" is definitely a novel that sticks with you. With its blend of adventure, fantasy, mystery, and even a dash of sci-fi, it's quite the unique cocktail. The premise alone – an immortal being observing the rise and fall of civilizations – is enough to grab your attention. Initially, I was drawn in by the sheer originality of the concept. The idea of an ancient human, the last of her kind, watching over a new race struggling with magic and their own evolution is fascinating. It felt like a grand-scale social experiment, viewed through the lens of someone ...
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Completed
6
#6 PICK
Utsuro no Hako to Zero no Maria
4.7
(509 ratings)
Genre: action, drama, horror
Utsuro no Hako to Zero no Maria, or The Empty Box and the Zeroth Maria, tells the sinister story of Kazuki Hoshino, who is almost madly attached to his everyday life, and his antagonist Aya Otonashi, who suddenly transfers into his class—for the 13,118th time. She majestically announces to “brea...
First Impressions
"Utsuro no Hako to Zero no Maria" (Hakomari), where do I even begin? This series is a trip, a wild, psychological, romantic, and sometimes horrifying ride that had me hooked from the first volume. I went in expecting a mind-bending mystery, and while I got that, I also found a story that explores the depths of human desire and the consequences of wish fulfillment. The initial volume throws you headfirst into a non-linear narrative, a time loop that's as confusing as it is captivating. I'll admit, it took me a bit to get my bearings, but the intrigue was enough to keep me pushing forward. The p...
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Completed
7
#7 PICK
Mahouka Koukou no Rettousei
4.4
(516 ratings)
Genre: action, martial arts, mystery
Magic. It is a product of neither legends nor fairy tales, but instead has become a technology of reality since a time unknown to people.
First Impressions
Mahouka Koukou no Rettousei is a series that has definitely left an impression on me. It’s a blend of sci-fi, magic, and school life that creates a unique world, but it’s not without its quirks. Initially, I was drawn in by the concept of a world where magic is intertwined with technology. The idea of a magic academy with a protagonist who seems like an underdog but is secretly powerful is a classic setup, and I was eager to see how Mahouka would execute it....
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Completed
8
#8 PICK
NPC Town-building Game
4.4
(346 ratings)
Genre: fantasy, mystery, seinen
An unknown parcel arrives to Yoshio, a 30-year-old NEET. The content is a game disk titled “The Village of Fate.
First Impressions
I dove into "NPC Town-building Game" with a mix of curiosity and caution, given the divided opinions I'd seen. The premise – a NEET protagonist becoming a god in a village sim – definitely piqued my interest. Was it a heartwarming tale of self-discovery or a preachy lecture on societal expectations? Let's unpack it. Initially, I was drawn in by the slice-of-life aspects and the protagonist's relatable struggles. The idea of a 30-year-old recluse finding purpose through a seemingly simple game was compelling. The early chapters focus on his relationship with the villagers and his gradual reinte...
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Completed
9
#9 PICK
Gekkou
4.6
(394 ratings)
Genre: mystery, psychological, romance
Gekkou, or “Moonlight”, is about the peculiar relationship between a cynical boy and a perfect girl. Said cynical boy is Nonomiya who spends day in day out in boredom, taking refuge from his dull life in his imagination.
First Impressions
"Gekkou," with its intriguing title and promise of mystery, definitely piqued my interest. Diving in, I found a novel that seems to have strongly divided its readership, eliciting both fervent praise and sharp criticism. My own experience landed somewhere in the middle, appreciating some aspects while feeling underwhelmed by others. The initial setup is classic light novel fare: a cynical protagonist, a beautiful and mysterious female lead, and a series of strange events that quickly pull you into the narrative. I was immediately drawn in by the mystery surrounding the female lead and the prot...
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Completed
10
#10 PICK
Shuumatsu Nani Shitemasu ka? Isogashii desu ka? Sukutte Moratte Ii desu ka?
4.7
(338 ratings)
Genre: drama, fantasy, mystery
Five hundred years have passed since the humans went extinct at the hands of the fearsome and mysterious ‘Beasts’. The surviving races now make their homes up on floating islands in the sky, out of reach of all but the most mobile of Beasts.
First Impressions
This title is quite a mouthful, but don't let that deter you. "SukaSuka," as it's often abbreviated, has proven to be a truly memorable experience. It's a story that burrows under your skin and stays with you long after you've finished reading. Initially, I was drawn in by the unique premise. A lone human, awakened in a world populated by beastkin and fairies, felt immediately compelling. The early chapters paint a picture of a man grappling with immense loss, searching for a place to belong in a world that is both foreign and hostile. This feeling of displacement and the yearning for connecti...
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Completed
11
#11 PICK
I Reincarnated as the Little Sister of a Death Game Manga’s M*rder Mastermind and Failed
4.4
(220 ratings)
Genre: horror, mystery, psychological
One day, Mai remembers that her perfect stepbrother is a character in a death game manga and that one year later he will hold a death game involving all of his classmates, killing his sister in the process. Mai plans a variety of surprises for her stepbrother every day based on what he said in t...
First Impressions
This title certainly grabbed my attention, and after diving in, I found a story that's both twisted and surprisingly adorable. The premise is a fresh take on the reincarnation trope, throwing the protagonist into a world of her own making to try and circumvent a future filled with death and despair. It's a wild ride, and I can definitely see why so many readers are hooked. The initial chapters immediately establish a sense of danger and intrigue. The dynamic between the protagonist, Mai, and her stepbrother, Makoto, is unsettling yet fascinating. Mai's eccentric attempts to "surprise" Makoto a...
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Conclusion

These completed Japanese mysteries all have proper endings, which matters for a genre built around resolution. Some incorporate supernatural elements, others stay grounded in realistic detection. The puzzle quality varies—some are tightly constructed, others rely more on atmosphere. I'd recommend checking individual synopses to find mysteries that match your preferred style.

Frequently Asked Questions

Our rankings consider multiple factors: reader ratings (40%), popularity and reading lists (25%), review quality (20%), and editorial assessment (15%). We update regularly to reflect new releases and changing reader preferences.

We update our rankings monthly to ensure they reflect the latest reader ratings and new novel releases.

How We Create Our 2026 Rankings

Our 2026 novel rankings are created through a comprehensive, data-driven process that combines quantitative metrics with qualitative editorial review. Here's how we ensure our rankings reflect the best novels available today.

Data Collection

We aggregate reading data, ratings, and engagement metrics from thousands of readers across multiple platforms, updated regularly throughout 2026.

Community Input

Reader ratings and reviews form the foundation of our rankings. We weight votes based on verified reading history to ensure authenticity.

Quality Scoring

Each novel receives a composite score based on average rating, vote count, reading list additions, and reader retention metrics.

Editorial Review

Our editorial team reviews top candidates for writing quality, translation accuracy, and overall reader experience.

Regular Updates

Rankings are refreshed quarterly to reflect new releases, updated ratings, and shifting reader preferences in 2026.

Transparency

We publish our methodology openly so readers understand exactly how novels earn their positions in our rankings.

Our 2026 Ranking Criteria

40%Reader Rating Score (weighted by vote count and recency)
25%Popularity Metrics (reading list additions, active readers)
20%Engagement Score (comments, reviews, recommendations)
15%Editorial Assessment (writing quality, translation, completeness)

Last updated: January 27, 2026 | Rankings reflect data collected through 2026

Ranked Novels

Kumo Desu ga, Nani ka?

First Impressions

Shini Yasui Kōshaku Reijō to Shichi-nin no Kikōshi

First Impressions

Fake Saint Of The Year

First Impressions

I Favor the Villainess

First Impressions

She Was Both Called God, as Well as Satan

First Impressions

Utsuro no Hako to Zero no Maria

First Impressions

Mahouka Koukou no Rettousei

First Impressions

NPC Town-building Game

First Impressions

Gekkou

First Impressions