AI Novel Tops Japan's Biggest Fiction Website, Sparking Literary Uproar

In a development that has sent shockwaves through Japan's literary community, an AI-generated novel has claimed the top spot in the daily comprehensive rankings on Kakuyomu, a popular web fiction site launched in 2016 by Kadokawa, one of Japan's largest publishers. 

The novel hit #1 on Monday and ignited passionate discussions on social media about the role of artificial intelligence in creative writing, with users divided between those championing innovation and others warning of the potential demise of human-driven storytelling.

Kakuyomu, known for hosting a wide array of genres including fantasy, science fiction, romance, and fanfiction, allows aspiring writers to publish serialized stories for free. Many of the more popular novels go on to be published in print. The platform's rankings are driven by metrics such as page views, favorites, and engagement, making them a key pathway for authors to gain visibility and even monetize through incentives like ad revenue.

The controversial novel, described as a women's-oriented isekai (fantasy) reincarnation love story, leverages AI to produce content at an astonishing pace, around 100,000 kanji characters per day. The novel is titled "I Bumped Into a Girl at a Corner and Used Healing Magic on Her, Curing Her of an Incurable Disease and Blindness, and She Became Very Attached to Me."

The story follows Yuuki, a former office worker who is transported to another world by God and granted overpowered healing magic. He cures Lunaria, a duke's daughter suffering from an incurable disease and blindness. The two fall in love, of course.

What made the project explosive wasn’t just that it was AI-written—it was the speed, with the author publishing so quickly it exploited Kakuyomu’s algorithm, which rewards frequent updates, total page views, and follower growth. The result was a self-perpetuating surge: more chapters (and the subsequent AI-written notoriety) meant more clicks, more visibility, and more engagement, propelling the story to the platform’s No. 1 daily ranking.

In doing so, the author, who uses the name Natsumi Nai, exposed how easily generative tools can overwhelm human-paced ecosystems and forced Japan’s biggest web-novel community to confront an uncomfortable question: What, exactly, counts as writing in the age of AI?

A sincere apology

"I sincerely apologize for not providing sufficient explanation to you all regarding the writing methodology for this work," she posted. "This work was primarily written using AI technology, and while I mentioned this in my profile, I should have made it clear in the first place readers would see it. I sincerely apologize for this lack of consideration."

The novel did particularly well on the site, with the first episode alone hitting approximately 50,000 page views, and potentially earning Natumi Nai tens of thousands of yen monthly (10,000 yen = about $65). Kakuyomu has a royalties program that allows authors to earn a share of advertising revenue based on the number of page views their work receives.

Because Kadokawa owns manga magazines, anime production committees, and merchandise divisions, a successful Kakuyomu novel can be fast-tracked into becoming a full-fledged media franchise, all handled within the same corporate ecosystem.

Kakuyomu hosts an annual web novel contest, considered a major industry event. Winning or even placing as a finalist in one of the categories is one of the most reliable pathways to getting your work published as a light novel (akin to a novella), which then opens the door for manga and anime adaptations.

The future of AI publishing

This is not the first time AI has caused a ruckus on Kakuyomu; a similar incident occurred in July, when another AI-assisted work topped the charts. However, the latest event has amplified concerns, as the author's method involves using templates to guide AI generation, resulting in readable but potentially inconsistent long-form narratives.

Critics pointed out that while the text mimics successful structures from existing human works, it risks homogenizing content and burying original voices under sheer quantity. The backlash has been swift and vocal on platforms like X , where users have been venting fears of AI "flooding" creative spaces.

Most of the criticism on X and the publishing site itself revolved around the idea that AI doesn't compete fairly, since it draws from unauthorized machine learning datasets trained on human-authored works—including an incident where 120,000 Kakuyomu stories were collected without permission and later removed at Kadokawa's request. Users worry that the flooding could reduce visibility for individual authors, shrink the overall user base (since many writers are also readers), and dilute ad-based incentives by spreading fixed budgets across more content.

On the other side, defenders emphasize creative freedom and the democratization of writing. They contend that rankings should evaluate the final product. Proponents note that effective AI use still requires human skill in plotting and guidance, and that such works can surpass the vast majority of amateur human novels in quality, potentially elevating the overall standard by weeding out mediocrity.

They argue that in a market-driven system, technical innovation like AI is inevitable and should be embraced rather than restricted. Others suggest mandatory labeling of AI-generated works for transparency or platform regulations to prevent abuse while allowing AI as a tool.

This controversy arrives amid a global reckoning with AI in the arts, following high-profile cases like Japanese author Rie Kudan's Akutagawa Prize-winning novel, which incorporated about 5% ChatGPT-generated content in 2024.

Meanwhile. Natsumi Nai continues to crank out light novels at an extraordinary rate. She appears to be adding a chapter every day to a dozen novels, including the destined-to-be-classic, "Although She Is an Abandoned Princess, She Has Joined Forces With Her Fluffy Friends to Create the Strongest Agricultural Nation."