Manga-Based English Learning App "Langaku" Surpasses 1 Million Downloads! Featuring over 100 hit titles readable in both Japanese and English, users unite for the "100 Million Words Challenge"

Celebrating 1 million downloads and its 4th anniversary, Langaku launches a community event where all users collaborate to achieve a combined total of 100 million words read.

Mantra Inc. (Headquarters: Bunkyo-ku, Tokyo; CEO: Shonosuke Ishiwatari) is proud to announce that Langaku, its manga-based extensive English reading app, officially surpassed 1 million cumulative downloads in May 2026 and celebrated its 4th anniversary in June 2026.

Langaku offers a unique reading experience that allows users to seamlessly switch between Japanese and English versions of the same manga, a lineup that has now grown to over 100 titles. By simply tapping a panel, users can instantly switch between languages. The app also allows learners to adjust the ratio of English text based on their proficiency and daily goals. This ensures that even beginners can easily maintain a consistent extensive reading habit while immersing themselves in the worlds of popular manga.

To commemorate these milestones, Langaku is launching its first-ever community event, the "100 Million Words Challenge." This 14-day event invites the entire user community to work together and reach a collective goal of reading 100 million English words.

Looking ahead to its 5th anniversary, Langaku aims to further expand its title lineup, continuously refining the experience of reading manga naturally in both Japanese and English. Our goal remains to deliver a delightful reading experience that enables more users to naturally engage with vast amounts of English through the manga they love.

■ Surpassing 1 Million Downloads on its 4th Anniversary


Since its launch in 2022, Langaku has redefined the concept of extensive English reading by leveraging the power of manga. Guided by the vision of "improving English skills naturally while preserving the pure joy of reading manga," the app has provided a rich, immersive learning environment.

By catering not only to advanced learners but also to those who feel intimidated by traditional English study, Langaku offers an accessible, engaging platform that continues to welcome a rapidly growing user base.

As it reaches its 4th year of service, Langaku has officially achieved over 1 million cumulative downloads. We express our deepest gratitude to our users who enjoy manga and English through the app every day, as well as to the authors, publishers, and partners who have graciously authorized the inclusion of their works.

■ Title Lineup of Simultaneous Japanese-English Manga Exceeds 100 Works


The majority of manga available on Langaku are not independent translations by the company, but rather the official English editions published and distributed globally. This allows users to learn natural, real-world English expressions used by native speakers, using the storyline and illustrations to intuitively grasp the context.

What sets Langaku apart is that it goes far beyond simply reading manga in English. It allows users to effortlessly jump back and forth between Japanese and English without friction, adapting to their specific English level and learning style.

Whenever users encounter an unfamiliar expression while reading in English, a single tap on the panel instantly switches the text to the Japanese version. There is no need to flip back pages or look up words in a separate dictionary. Learners can stay fully immersed in the story while naturally understanding the meaning and subtle nuances of English phrases.

Furthermore, Langaku allows users to customize the volume of English text. Whether they want to "read heavily in English today," "take it easy with more Japanese because this title is challenging," or "start slowly to get used to English," users can adjust the balance between English and Japanese according to their mood or learning mode.

The app also features comprehensive learning support tools, including audio narration for all dialogue and vocabulary (with an auto-play mode), built-in dictionary lookups, and AI-driven explanations that clarify context-specific idioms and slang as users read.

In short, having 100 titles on Langaku means much more than just a numerical catalog. It means that over 100 popular manga series are fully optimized for a seamless bilingual reading experience—complete with adjustable English text ratios, audio, dictionaries, and AI explanations for stress-free learning.

Langaku plans to actively expand this lineup further. Moving toward its 5th anniversary, the team is fully committed to adding more popular titles to deliver this unique, seamless reading experience across a broader spectrum of works.

■ 1 Million Downloads Commemorative Event: "100 Million Words Challenge"

To celebrate the 1 million download milestone and the 4th anniversary, Langaku is hosting the "100 Million Words Challenge," a community-driven event designed to make extensive reading a shared experience.

In this cooperative event, all participating users combine their efforts to read a cumulative total of 100 million words within 14 days. The word count of every page read during the period is added to the community’s overall progress. Once the final goal is met, all qualifying participants will receive special rewards.

Rather than studying English in isolation, this initiative lets users nationwide collaborate, sharing the excitement of moving through stories while enjoying the collective satisfaction of achieving a massive milestone. The focus is not on competing in individual rankings, but on reaching a single, shared goal as a community.

Simply reading your favorite titles contributes to everyone's progress. Even reading a small amount qualifies users for the milestone rewards, while reading more increases the chances of winning the simultaneous lucky draw campaigns.

"100 Million Words Challenge" Event Overview:

  • Event Period: June 22 (Mon) 18:00 – July 6 (Mon) 23:59 [14 Days]
  • Eligibility: All users who enter the event via the app.
  • How to Participate: Simply tap the "Enter" button on the home screen banner.

Community Milestone Reward If the community reaches the collective goal of 100 million words, all users who meet the individual criteria will receive 5 Tickets!

Simultaneous Lucky Draw Campaign Users who read extensively during the event will be automatically entered into a draw to win prizes. A total of 50 winners will receive up to 10,000 coins. The more you read, the higher your chances of winning.

Friend Invitation Campaign Users can invite friends by sharing their referral code via the "Share Results" feature to earn extra tickets. Invite your friends and aim for 100 million words together! *Detailed participation conditions, reward structures, and lucky draw rules are available via the in-app announcements.


■ Simultaneous X Campaign: "How Langaku Changed My Routine!"

To mark the 4th anniversary, Langaku is running a user-voice campaign on X (formerly Twitter). By quote-reposting the official campaign post from the Langaku account and sharing personal stories under the theme "How Langaku Changed My Routine!"—such as positive changes in study habits or noticeable improvements in English skills—four lucky participants will be selected via lottery to receive 4,000 Langaku coins.

  • Campaign Name: "How Langaku Changed My Routine!" 4th Anniversary Campaign
  • Campaign Period: June 22 (Mon) – July 3 (Fri) 23:59
  • How to Join: Quote-repost the designated post from the official Langaku X account (@langaku_app) with a post matching the theme.
  • Prize: 4,000 Langaku Coins (4 winners selected by draw)
  • Official Langaku X: https://x.com/langaku_app
■ Delivering an Extensive Reading Experience: "The More You Enjoy, the More You Grow"

The key to maintaining an English learning routine is making it effortlessly sustainable. Langaku ensures this by giving users total control over their reading, allowing them to flip between languages instantly and adjust readability based on their individual English level.

The "100 Million Words Challenge" is designed to boost daily reading habits and keep learning motivation high. While extensive reading can sometimes feel lonely or difficult to sustain individually, working toward a shared community goal makes the journey more enjoyable and encouraging.

Langaku will continue to support users in their English learning journeys by delivering innovative educational experiences that perfectly blend the entertainment value of manga with effective language acquisition.

■ About Langaku

Langaku is an app that brings a rich, extensive English reading experience to life through manga. Featuring over 100 popular titles like ONE PIECE and Demon Slayer: Kimetsu no Yaiba, the app enables users to naturally build their English proficiency while enjoying world-class stories.

Proprietary Learning Support Features:

  • Instant English/Japanese switching with a simple tap on any panel.
  • Full audio narration for all dialogue and vocabulary (includes an auto-play mode).
  • Integrated dictionary and AI explanations for every line and word to check meanings on the spot.
  • AI-driven commentary tailored to the context, explaining unique idioms and slang.
  • Adjustable English text volume to match the user's specific learning pace.
  • Vocabulary and dialogue saving features for easy review later.
  • Data-driven reading logs that visualize cumulative learning progress.

Extensive reading is widely recognized as one of the most effective ways to train the brain to process English naturally. Experience "study-free language learning" where your English skills grow naturally while you read the manga you love.

App Specifications:

■ About Mantra Inc.

Founded in 2020 with the slogan "Bringing manga to the world in their own languages," Mantra Inc. specializes in the research and development of AI technology tailored specifically for manga. The company provides Mantra Engine, a high-speed manga translation tool, and Langaku, the manga-based extensive English learning app.

Mantra's innovations have earned numerous accolades, including the HONGO AI Award (2019), Weekly Toyo Keizai’s "Amazing Ventures 100" (2020), the AAMT Nagao Award (2021), the JEITA Venture Award's Early Edge Prize (2022), the Electronic Publishing Award's Challenge Mind Prize (2024), the Google Play Best of 2025 (Self-Improvement Category) Grand Prize (2025), and the Appliv Best App Award (Learning App Category) Excellence Prize (2025).

Company Profile:

  • Company Name: Mantra Inc.
  • Representative: Shonosuke Ishiwatari, CEO
  • Address: 2F Sumitomo Fudosan Iidabashi Bldg., 2-3-21 Koraku, Bunkyo-ku, Tokyo 112-0004
  • Established: January 28, 2020
  • Capital: 1,000,000 JPY
  • Business Description: Research and development of machine translation technology optimized for manga, alongside the provision of translation and English learning services.
  • URL: https://mantra.co.jp
■ Media Contact

Mantra Inc. PR Representatives: Norimine / Funakoshi
E-mail: info@mantra.co.jp

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