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AI Legal Lab

A media by legal professionals, for legal professionals, gathering the information needed to put legal AI to full use in everyday legal work.

Data Breach & Cyberattack News

See all listed incidents

Based on official announcements by companies and organizations in Japan.As of October 28, 2026

Listed incidents in numbers

Listed incidents
189 incidents
Incidents with confirmed leaks
85 incidents
Possible leaks / investigations
92 incidents
Incidents with service / business outages
85 incidents

Gross counts of exposed information

Reference sums excluding image metadata

Information confirmed exposed
Approx. 162,450,795 reported items
Information potentially exposed
Approx. 195,140,203 reported items

Including image metadata

Information confirmed exposed
Approx. 828,850,795 reported items
Information potentially exposed
Approx. 195,140,203 reported items
Breakdown and sources

Listed incidents by month

By the latest announcement listed for each incident

  1. Apr 20262
  2. May 20265
  3. Jun 202611
  4. Jul 20268
  5. Aug 202610
  6. Sep 202636
  7. Oct 2026117

  1. Reopening target announced; suspension continues

    Leak confirmed

    Rakus Light Cloudblastmail

    All customer-contract information; non-contract information exposed for 345 contracts

  2. Thirteenth report / attacker-site domain suspended

    Possible leak

    GMO InternetOnamae.com Desktop Cloud

    26,739 potentially affected servers; exposed-data count undisclosed

  3. Related update

    Leak confirmed

    YmirlinkCuenote FC / Cuenote BASE

    FC: 51,628,280 records in gross; BASE: 190 customer records

  4. Seventh report / investigation completed and recovery support

    Lookup confirmed

    IDC Frontier

    Up to 31 personal-name/email records; 495 organizations affected

  5. Possible leak

    Japan External Trade Organization (JETRO)e-Venue

    Up to 133 records

Methods and coverage

See all listed incidents

Latest articles

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  1. Fundraising and Investment Agreements

    Equity Compensation Options: How RS and RSUs Differ from Stock Options

    8 min
  2. Fundraising and Investment Agreements

    Legal Management of Subsidiaries: Group Company Rules and Internal Controls

    7 min
  3. Fundraising and Investment Agreements

    Share Buyback Procedures and Distribution Limits: Purchasing Shares from a Departing Shareholder

    8 min
  4. Startup Legal

    Amending Articles of Incorporation in Japan: Procedures, Registration and Key Provisions

    10 min
  5. Fundraising and Investment Agreements

    Liability Limitation, Indemnification and D&O Insurance: Preparations Before Appointing Outside Officers

    8 min
  6. Contract Review

    Cross-border e-commerce terms: consumer sales, governing law and jurisdiction

    8 min
  7. Fundraising and Investment Agreements

    Flipping to a U.S. Holding Company: Delaware Incorporation, Shareholders and Contracts

    10 min
  8. AI Service Legal

    GDPR and DPAs for Japanese Companies: Scope and Cross-Border Data Contracts

    10 min
  9. Contract Review

    Governing Law and Arbitration in International Contracts: Resolving the Last Two Clauses

    8 min
  10. Contract Review

    Reading English-Language Contracts: Structure, Modal Verbs and Liability Clauses

    7 min

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Generative AI news

See all generative AI news

Each item links to its source.

  1. Global / Enterprise & infrastructure

    Retell AI details its use of OpenAI models for voice agents

    View primary source: OpenAI (official) (Open external link)

  2. Global / Enterprise & infrastructure

    OpenAI and Oracle expand application integration and procurement options

    View primary source: OpenAI (official) (Open external link)

  3. Global / Enterprise & infrastructure

    Check Point describes vulnerability analysis and defenses using Daybreak

    View primary source: OpenAI (official) (Open external link)

  4. Global / Enterprise & infrastructure

    Anthropic expands Claude discounts for US government agencies

    View primary source: Anthropic (official) (Open external link)

  5. Global / Research & safety

    Anthropic studies alignment between agent decisions and human preferences

    View primary source: Anthropic (official) (Open external link)

  6. Global / Research & safety

    Anthropic reports vulnerability research using an unreleased model

    View primary source: Anthropic (official) (Open external link)

See all generative AI news

Topics

Contract Review116 related articles

116 related articles

Contract review playbooks, clause-level checkpoints, and practical review workflows.

  1. Legal Issues in Vertical Short Dramas: Performer Agreements, Secondary Use and Overseas Distribution

    14 min

  2. English-Language Contracts for Overseas Expansion: Choosing the Governing Law and Seat of Arbitration, and Provisions Your Team Can Operate

    5 min

  3. Carbon Credits and GX Initiatives: Regulation of Environmental Claims and Points to Check in Purchase Agreements

    6 min

  4. Change of Control Clauses: Points to Check for M&A, Capital Policy and Continuity of Business Relationships

    4 min

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Fundraising and Investment Agreements50 related articles

50 related articles

Startup financing topics including J-KISS, investment agreements, shareholders agreements, preferred shares, stock options, and capitalization.

  1. Trust-Type vs. Paid Stock Options: Taxation and Issuance Procedures

    15 min

  2. Convertible Notes vs. J-KISS: Repayment Obligations, Maturity and Conversion Terms

    15 min

  3. Startup Articles of Incorporation and Corporate Governance Structure: Provisions to Revisit When Raising Capital and How They Divide Roles with the Shareholders' Agreement

    15 min

  4. J-KISS Conversion (Exercise) Procedures: A Practical Guide to Avoid Scrambling at Series A

    15 min

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M&A Legal43 related articles

43 related articles

M&A legal work including legal due diligence, SPA review, representations, indemnities, closing, business transfers, and sell-side preparation.

  1. What Are Key Person Clauses and Retention? Closing Conditions and Measures to Keep People

    9 min

  2. What Is an Earn-Out Clause? A Mechanism for Bridging Valuation Gaps in M&A and Its Dispute Risks

    12 min

  3. What Is W&I Insurance (Representations and Warranties Insurance)? Risks Covered in M&A and the Seller's Liability

    8 min

  4. How to Choose an M&A Structure: A Legal Perspective for Narrowing Down Share Acquisitions, Business Acquisitions and Reorganizations

    12 min

Open theme pageView LegalAgent M&A Support

Law Changes Calendar

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The effective-date schedule of Japanese law changes affecting corporate practice, with effective dates, outlines and the businesses affected. The next scheduled changes are below.

Effective dateOutline and scope
2026.10.01–12.02 (by region)Revision of regional minimum wages (FY2026)Labor & HR / Businesses that employ workers
Shift of the consumption tax exemption system to a refund model (tax-free shop system)Tax & retail / Retailers operating tax-free shops (export goods sales sites)
2026.11.01 (planned)Amendment to the Logistics Efficiency Act (relay transport)Logistics & business regulation / Logistics operators conducting relay transport and operators of relay transport facilities
Digital administrative penalty hearings under the FIEA and CPA ActFinance & disclosure / Listed companies, financial instruments business operators, audit firms, etc.

See all law changes

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What is AI Legal Lab?

LegalAgent AI Legal Lab is a media site that explains, as clearly as possible, how to put generative AI to work in everyday corporate legal practice.

As a law firm for the generative-AI era that already uses generative AI to the fullest in real legal work, Legal Agent shares its hands-on know-how and practical methods in plain language.

Media coverage

  1. Representative Attorney Asato contributed an article to the September 2026 issue of Kaisha Homu A2Z (Japanese) (Open external link)
  2. Representative Attorney Asato was featured in a NewsPicks special report (Japanese) (Open external link)
  3. Representative Attorney Asato and the AI Legal Lab were featured in Houritsushoku.com's "Law x AI" roundup (Japanese) (Open external link)