KASANEGI

KASANEGI

かさねぎ

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ABOUT

About Kasanegi

We use AI to find a new dimension in data that already exists. Kasanegi is a research and development studio in Osaka, Japan, built on that single idea.

Kasanegi runs on one founder, a geology specialist, and a team of AI agents. The founder sets the questions and makes the final calls, as principal investigator. Research design, checking against primary sources, data processing and verification, and software engineering are handled by AI agents centred on Claude Code, organised as our research and engineering layer. Our Claude Code work sessions number more than 6,600.

Working this way, we run research, software and a revenue-earning system in production. At the centre is research to find undiscovered meteorite craters across Japan's entire terrain. The same idea and the same way of working have also produced an app that turns the manga you love into language study material, data APIs that turn Japan's public data into tools for AI agents, and a video production system in which AI produces everything from script to upload, fully automatically. The video production system earns real revenue and supports our research and development.

We are now undertaking a major integration, bringing everything we build into a single foundation that uses AI to create new value from existing data. This includes the data APIs we have published since before our founding, the processing behind our research, the technology that layers two languages, the video production system, and much more development not listed here. Meanwhile, the ten APIs of JP Local Pack remain open free of charge, as one example from our family of data APIs.

The name comes from kasanegi (重ね着), dressing in layered garments, as in the twelve-layered jūnihitoe. Layering makes things beautiful and practical, and creates new value. We layer AI onto data and technology onto knowledge, and keep evolving. That is the work of Kasanegi. We gave our language app the same name. Our code runs to more than 450,000 lines across four businesses, with more than 1,800 commits.

0
page mix-ups across 60 and 54 page pairs from two titles, matched by artwork without relying on page order
36/36
tiles at Oikeyama where we reproduced Japan's nationwide red relief image map to within one colour level

PROJECTS

What we work on

01 · Research

Searching all of Japan for undiscovered meteorite craters

Building on the latest red relief image map of all of Japan, this research uses machine learning to train AI on the world's known impact structures, so that the AI can identify undiscovered meteorite craters across the terrain of the entire country. It works at a speed, and in a way, that checking by eye and overlaying data by hand cannot match.

In Japan, Oikeyama in Nagano Prefecture has been reported as a meteorite crater. The country's steep, forest-covered mountains are thought to hide craters that remain undiscovered. Identifying craters in imagery covering all of Japan requires advanced AI built on machine learning.

AI agents carried out preparation on a scale no human team could reach. The AI learns from the world's impact structures. We have compiled 354 of them, across 67 countries and regions, into a single inventory, and linked 2,011 papers to 240 of those structures. For 48 known craters, we have made red relief image maps from publicly available 1 m elevation data. We have also identified the calculation behind Japan's nationwide red relief image map down to its formulas and constants, and reproduced it at Oikeyama to within one colour level. This lets us compare terrain worldwide and in Japan by the same measure.

Beyond terrain, we assess the quality of Japan's nationwide gravity and airborne magnetic surveys against primary sources and the actual data. Candidates the AI puts forward are verified by our founder, a certified mineral appraiser and geology specialist, who examines the rocks in the field. The same method extends to terrain worldwide, to the surface of the Moon, and to the discovery of kofun burial mounds.

354
impact structures worldwide in our inventory, across 67 countries and regions, including 226 confirmed sites
2,011
papers linked to 240 structures in the inventory
48
known craters made into red relief image maps from 1 m terrain data
Red relief image map of Oikeyama, Nagano Prefecture
Red relief image map of the Oikeyama crater, Nagano Prefecture, made from 1 m elevation data from the Geospatial Information Authority of Japan.

02 · App

kasanegi: crossing the language barrier through manga

The kasanegi app lets you read two language editions of the same manga layered page by page on your device. Enter two URLs, and the whole chapter is layered at once. Move the round lens, and just that area switches to the other language. The manga you already love becomes your language study material.

Pages are paired not by their order but by comparing the artwork, then aligned and layered. On one chapter of a published manga, all 60 page pairs were matched without a single mix-up, and all 54 on another title. Images never leave the device.

Because the layering works from the artwork, it is not tied to any particular pair of languages. Sharing its name with the company, the app is the most accessible form of the idea behind Kasanegi. It runs on Android and PC, and you can see it for yourself right now in the browser demo. The PC beta has been well received, and more than twenty people have said they want to use it as a paid product.

60
page pairs matched without a mix-up on one chapter of a published manga
3
platforms it runs on: Android, PC and the browser demo
Pages from two language editions layered, with the other language visible only inside a round lens

03 · Data API

Japan's public data, in a form AI agents can use directly

We turn tables and registers published by Japan's public institutions into APIs that AI agents and software can use in a single call. Sources include the National Tax Agency, the Japan Health Insurance Association (Kyokai Kenpo), the Ministry of Health, Labour and Welfare, the Cabinet Office, and gBizINFO from the Ministry of Economy, Trade and Industry. Since before our founding, Kasanegi has developed a family of these data APIs and published them on kasanegi.com, on a marketplace for developers and over MCP.

We are now integrating that family of data APIs into the foundation that brings all of Kasanegi together. In the meantime, so that you can work with the real thing, the ten APIs of JP Local Pack are open free of charge, with no sign-up. JP Local Pack is one approach within the family: public data for back-office work in Japan.

Even this one example is exact: the withholding income tax API holds all 1,856 cells of the National Tax Agency's monthly withholding table and matches the official table cell for cell.

Beyond the APIs we have opened, we hold further data APIs: matching and enriching company records, corporate disclosures such as annual securities reports, and searching grants and judging eligibility, all built to connect public data directly to an AI agent's decisions. As our AI resources grow, we open more of them.

Our data APIs are built so that AI agents can find and use them on their own. With an MCP server, OpenAPI and llms.txt in place, an AI agent receives the usage instructions and endpoints, and can put the APIs to work directly.

1,856
cells of the National Tax Agency's withholding tax table, every one matched, even in JP Local Pack, one example from the family
5 million
entries in the qualified invoice issuer registry, which an AI agent can look up in one call
10
APIs open free of charge now, as one example from the family, with MCP support

GET api.kasanegi.com/preview/v1/local/payroll/calc-by-salary?monthly_salary=300000&pref_code=13&age=30

Health insurance
14,775
Child and child-rearing support contribution
345
Employees' pension
27,450
Employment insurance
1,500
Withholding income tax
6,320
Total deductions
50,390
Take-home pay
249,610
The actual response (in yen) from JP Local Pack, one example from the family, for a monthly salary of ¥300,000 in Tokyo at age 30. The figures follow the fiscal 2026 tables of Kyokai Kenpo and the National Tax Agency.

04 · System

A fully automated AI video production system that earns revenue

With Claude Code, we developed a video production system in which AI handles everything from writing the script to editing and publishing, fully automatically. The system runs seven channels across different genres and languages.

What it makes is not low-quality AI content or videos padded with invented stories, but videos worth people's time. Facts are checked against their sources through a fixed procedure, and the AI is never allowed to invent them. The founder sets the policy and the final standard. Our newest channel reached one million total views within a month of launch.

Our research and development carries a fixed AI subscription cost of more than US$400 a month at the minimum. The videos earn real revenue, which covers that cost and our development costs while we keep expanding production. The two channels below are examples of what the system runs.

7
channels across different genres and languages, run by the system
1 million
total views reached by our newest channel within a month of launch

NEWS & HISTORY

News and history

  • Data API

    Opened the ten APIs of JP Local Pack free of charge, as one example while we integrate our family of data APIs. Payroll, social insurance, withholding income tax, consumption tax, national holidays, corporate numbers, qualified invoices and Peppol are all available to try with no sign-up.

  • News

    Relaunched our website. We are integrating all of Kasanegi, including the family of data APIs we have published since before our founding, into one foundation that uses AI to create new value.

  • App

    The Android app layered 60 page pairs from one chapter of a published manga without error.

  • Research

    Identified the calculation behind Japan's nationwide red relief image map down to its formulas and constants, and reproduced it at Oikeyama to within one colour level.

  • App

    The language app's page matching paired the pages of a published manga without error.

  • App

    Developed the PC version of the language app, with a round lens.

  • Channels

    Launched a new channel. It reached one million total views within a month of launch.

  • News

    Kasanegi was founded.

  • Channels

    Our video channel was approved for the YouTube Partner Program.

  • Data API

    Our data APIs were listed in a developer community directory of APIs for AI agents.

  • Data API

    Launched kasanegi.com and published our data APIs.

  • Data API

    Published Japan's public data as APIs that AI can use directly.

MEMBER

Founder

Tokitsugu Matsushita

松下 宗嗣

Founder

Certified mineral appraiser. Masason Foundation Scholar (third cohort). As a geology specialist, carried out mineral field surveys in the Izumi Group of Osaka Prefecture, and in 2019 published a paper on dawsonite from the Shindachi Formation in Chigaku Kenkyu. Developed and published data APIs for AI agents before founding Kasanegi in June 2026. Leads research and development at Kasanegi.

COMPANY

Company overview

Trade name
Kasanegi (Japanese: かさねぎ)
Founder
Tokitsugu Matsushita
Location
Osaka City, Osaka Prefecture, Japan
Founded
1 June 2026
Business
Development of a foundation that uses AI to create new value from existing data
Earth science research and development (terrain analysis with AI)
Development and provision of data APIs for AI agents
Planning and development of software, including the language app
Development and operation of an AI video production system
Track record
YouTube Partner Program (approved May 2026)
Data APIs listed on RapidAPI
Public MCP server (mcp.kasanegi.com)
Contact
contact@kasanegi.com

CONTACT

Contact

For enquiries about joint research, adopting our data APIs, the kasanegi language app, partnerships or press coverage, please contact us at the address below.

contact@kasanegi.com →