Japan legal data from official sources, structured for AI and legaltech.
Access 144,587+ Japanese laws, regulations, court decisions and regulatory materials from Japanese government, judicial and regulatory institutions across 17 official portals. Search Japanese legal data directly or connect it to your AI agent, legaltech product or research workflow through Lawstronaut's API and MCP server. Every record is linked to its official source and structured in the same format used across more than 150 jurisdictions.
144,587+
Japan legal records
17
official Japanese source portals
1,160
issuing authorities
Daily
updates
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Where does Lawstronaut hold the implementing rules for Japan's Act on the Protection of Personal Information (APPI)?
In the 個人情報の保護に関する法律施行令 (Order for Enforcement of the Act on the Protection of Personal Information) — the Cabinet Order (政令) that implements the APPI. The corpus tracks it version by version on the government's e-Gov portal, with the amendment effective 2 December 2024 the most recent point-in-time text.
Source: デジタル庁 (Digital Agency, Japan) — laws.e-gov.go.jp/law/415CO0000000507/20241202_506CO0000000260
Retrieved: 2026-08-11 · Version: 1 · Cited in-turn
The official Japanese sources we cover
Lawstronaut collects Japanese legal materials from official government, court, and regulator sources. Each record links back to its original source, with metadata such as issuing authority, publication date, legal link, portal, content type, and version where available.
Source categories: the national statute bank and official translations · courts and the judiciary · financial, competition, and consumer regulators · the data protection authority · tax, health-and-labour, and agriculture authorities · environment, energy, digital, transport, and meteorological ministries and agencies
- e-Gov Laws and Regulations (laws.e-gov.go.jp)
- Japanese Law Translation (japaneselawtranslation.go.jp)
- Courts in Japan / 裁判所 (courts.go.jp)
- Personal Information Protection Commission (ppc.go.jp)
- Financial Services Agency (fsa.go.jp)
- Japan Fair Trade Commission (jftc.go.jp)
- Consumer Affairs Agency (caa.go.jp)
- Ministry of Economy, Trade and Industry (meti.go.jp)
- Ministry of Health, Labour and Welfare (mhlw.go.jp)
- National Tax Agency (nta.go.jp)
- Ministry of the Environment (env.go.jp)
- Digital Agency (digital.go.jp)
Japanese legal source types covered
Japanese legal coverage includes primary legislation, secondary legislation, regulatory materials, court decisions, guidance, enforcement documents, and legislative history where available.
Legislation & Regulations
法律 (Acts), 政令 (Cabinet Orders), 省令・府令 (Ministerial Ordinances), 規則 (rules), and 告示 (public notices), taken directly from e-Gov Laws and Regulations (laws.e-gov.go.jp) and the official English translations on the Japanese Law Translation portal.
Legislative History
Amendment records and revised or partially-unenforced (一部未施行) versions of statutes and orders where available, version by version, each tied to its official source.
Regulatory Guidance & Enforcement
Guidelines (ガイドライン), public notices (告示), enforcement decisions, and press-release materials from Japanese regulators such as the Personal Information Protection Commission, the Financial Services Agency, the Japan Fair Trade Commission, and the Consumer Affairs Agency.
Case Law
Court and tribunal decisions from official Japanese sources, including judgments published by the Courts in Japan (courts.go.jp), each carrying its case number where available.
One Japanese legal data layer. Four ways to use it.
Lawstronaut API
Query Japanese laws, regulations, court decisions, regulatory guidance, and enforcement materials through a REST API. Use structured metadata, full text, Markdown, source links, and version history to power legaltech products, compliance workflows, and internal research tools.
GET /v2/contents?iso=JP&limit=20Lawstronaut MCP
Connect ChatGPT, Claude, Gemini, Cursor, and other AI agents to Japanese legal sources. Questions become live searches against the corpus and return citation-ready answers grounded in official Japanese materials — deployable in minutes, with no integration work.
AI Agent Integration
Give your legal AI agent same-turn provenance: it retrieves current Japanese legal materials — official source links, metadata, and full text — before generating an answer, with a citation and timestamp on every response.
Build with Lawstronaut
Build Japanese legal search, monitoring, compliance, research, and legal AI features without crawling, parsing, normalizing, and updating official sources yourself. We handle source discovery, ingestion, normalization, versioning, and change detection; you build the product.
What you can do with Japanese legal data
- Retrieve legal metadata, full text, Markdown, source links, and original source files where available
- Filter by jurisdiction, portal, issuing authority, authority type, language, status, and dates
- Access official legal links for citation and audit trails — citation, timestamp, and source link returned in the same turn
- Track point-in-time versions and article-level changes across Japanese legal materials
- Run Horizon Scanning — track what changed in Japanese law, when, and where, without manual monitoring
- Connect AI agents to official Japanese sources through MCP; use the API for search, monitoring, compliance, and AI ingestion workflows
- Build internal Japanese legal research tools without maintaining your own crawler stack
Why Lawstronaut for Japanese legal research
Japanese legal information is spread across the e-Gov statute bank, official translations, the courts, and a wide set of ministry and regulator portals. For humans, that means slow research, often across Japanese-only sources. For AI systems, it's a bigger problem: fragmented source access, inconsistent formats, missing provenance, and weak citation trails.
Lawstronaut turns those sources into one structured legal data layer — source links, metadata, full text, versioning, and API/MCP access. Your product or agent retrieves the legal source directly instead of relying on generic web search or unverified model memory. Every answer carries a citation, a timestamp, and a link to the official document — the provenance that makes a legal research platform defensible to auditors and regulators.
About Japan legal coverage
Japan is a civil-law jurisdiction. Statutes (法律) are enacted by the National Diet; consolidated legislation and subordinate regulations — Cabinet Orders (政令), Ministerial Ordinances (省令), and public notices (告示) — are published on the government's e-Gov portal (laws.e-gov.go.jp), with official English translations of many major laws on the Japanese Law Translation portal (japaneselawtranslation.go.jp). Court decisions are published by the judiciary on courts.go.jp. Regulatory guidance sits with bodies such as the Personal Information Protection Commission, the Financial Services Agency, the Japan Fair Trade Commission, and the Consumer Affairs Agency. Records are published in Japanese, with English translations available for many flagship statutes.
Japanese law moves steadily: flagship statutes such as the Act on the Protection of Personal Information are amended on regular cycles, financial, competition, and consumer regulators issue a continuous stream of guidance and enforcement decisions, and reforms — the 2020–2021 APPI amendments and the Digital Agency's data-governance work among them — keep evolving. The corpus flags partially-unenforced (一部未施行) versions so version state stays explicit, and point-in-time data straight from the official source is what keeps a Japanese legal research answer correct today.
Built for
Legaltech companies
Build Japanese legal search, monitoring, drafting, compliance, and AI research features without maintaining your own legal source pipeline.
Compliance & GRC teams
Monitor Japanese regulatory materials, guidance, enforcement updates, and legal changes across official sources — without a manual monitoring rota.
AI builders
Ground legal AI answers in official Japanese legal text, source links, and metadata — answers that survive an auditor.
Internal legal teams
Give lawyers and business users faster access to Japanese legal sources through AI agents and internal tools, without hiring a researcher per jurisdiction.
Frequently asked questions
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Start building with Japanese legal data today
Connect your AI to Japan's legislation, regulations, and case law through MCP or the API.