Internet Issues- View allLast updated: 2026-03-133 min read

Online Defamation: How to File a Sender Disclosure Request in Japan

Key Takeaways

  • Anonymous online defamers can be legally identified
  • The 2022 reform shortened the process to about 6-12 months
  • Typical damages range from ¥300,000 to ¥1,000,000 for individuals
  • ISP logs are deleted within 3-6 months, so act quickly
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What is Online Defamation?

Posts on social media, forums, and review sites that lower an individual's or company's social reputation may constitute defamation (Criminal Code Art. 230) or insult (Art. 231) under Japanese law.

Sender Disclosure Request Overview

The sender disclosure request (Provider Liability Limitation Act Art. 5) is the legal procedure to identify anonymous posters.

2022 Reform

The October 2022 reform streamlined the process from two stages to a single court proceeding, reducing the timeline from 1-2 years to approximately 6 months to 1 year.

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Typical Damages Awarded

  • Individual defamation: ¥300K-1M
  • Corporate reputation damage: ¥500K-3M
  • Sexual content: ¥1M-2M

Attorney fees for disclosure requests can be substantial. Legal fee insurance (弁護士費用特約) may cover most of the cost in some cases.

Types of Insurance to Check

  • Auto insurance rider: Many auto insurance policies include a legal fee rider that extends beyond traffic accidents to general legal disputes
  • Standalone legal fee insurance: Monthly premiums of a few thousand yen may cover online defamation claims
  • Internet trouble insurance: Specialized plans covering cyberbullying and personal data exposure, including disclosure request costs

Key Points

  • Coverage scope varies significantly by insurer
  • Pre-approval from the insurer is usually required before retaining counsel
  • Coverage limits typically range from ¥1M to ¥3M
  • Check existing policies (auto, home, health) — you may already have coverage attached

What You Can Do Without an Attorney

Not every step requires legal representation.

Self-Help Procedures

Transmission prevention requests (deletion requests) can be filed directly by the victim. The Ministry of Internal Affairs and Communications publishes a standard form (送信防止措置依頼書) that individuals can complete and send to site operators without an attorney.

Search result removal requests (Google, etc.) can also be submitted via each platform's online removal request form at no cost.

When an Attorney Is Strongly Recommended

  • Disclosure order application to the court: Drafting and filing petitions, negotiating with providers
  • ISP subscriber information disclosure: Requires technical and legal expertise
  • Damages litigation: Evidence gathering, legal arguments, trial representation

If cost is a barrier, Japan Legal Support Center (Houterasu / 法テラス) offers attorney fee advances for those meeting income criteria.

Required Documents for a Disclosure Order Application

When filing a disclosure order petition with the court, prepare the following:

DocumentDetails
Petition (申立書)Applicant's name/address, respondent (site operator or ISP), specific information sought, description of rights violated
Evidence (screenshots)Screen captures showing the post, including URL, timestamp, and username
Affidavit (陳述書)Written statement explaining how your rights were violated; describe specific harms (emotional distress, business damage, etc.)
Corporate certificateIf applicant is a company, certified copy of commercial register
Court filing feeRevenue stamps (typically a few thousand yen, varies by court)
Postal stampsFor court correspondence
URL listList of URLs for all posts subject to the disclosure request

Application Process

  1. Submit documents to the competent district court (based on applicant's or respondent's address)
  2. Court sends inquiry to the respondent (site operator) for written comments
  3. Court issues ruling — if granted, disclosure is ordered
  4. Use the disclosed information to proceed to ISP disclosure or damages claim

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This article provides general legal information and does not constitute legal advice. For specific legal issues, please consult with a qualified attorney.

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