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Privacy Policy

Effective date: April 29, 2026

This English text is provided for the convenience of non-Japanese readers. The Japanese version is the authoritative original and prevails in case of any discrepancy.

“my温泉手帳” (the “Service”) handles users’ personal information appropriately. This policy is drafted with Japan’s Act on the Protection of Personal Information (APPI) and the EU General Data Protection Regulation (GDPR) in mind.

1. Information We Collect

The Service collects the following information.

InformationPurpose
Email addressAuthentication and responding to inquiries
Display name (optional)Shown publicly as the poster’s name
Country / region (optional)Not public. Used for regional usage analytics
Preferred language (optional)Not public. Used for future multilingual support
Onsen analysis report images and textBuilding the database and providing the Service
Access and activity logsQuality improvement and fraud detection

2. Purposes of Use

  • Providing, maintaining, and improving the Service
  • User authentication and account management
  • Displaying user content (only the display name is made public)
  • Detecting and preventing misuse
  • Legal compliance and protection of rights

3. Disclosure to Third Parties

The Service does not provide users’ personal information to third parties except in the following cases.

  • When the user has consented
  • When disclosure is required by law
  • Minimum necessary provision to processors (such as Supabase Inc., Vercel Inc., and Google LLC). These providers act as data processors under the Service’s instructions.

3-2. About AI Processing

The Service uses generative AI to extract data from onsen analysis reports, generate explanatory text, and translate into multiple languages. For transparency, the processing is disclosed below.

ProcessingService usedData sent
OCR (text extraction)Google Cloud VisionUploaded image/PDF
Structured data extractionAnthropic Claude (Sonnet 4.6)OCR text (no personal data)
Explanatory text generation (features, bathing tips, benefits, cautions)Anthropic Claude (Sonnet 4.6)Extracted components, temperature, pH, indications, etc.
Multilingual translation (en / zh-TW / zh-CN / ko)Anthropic Claude (Haiku 4.5)Japanese explanatory text, facility name, address
Usage research (heating / water addition / circulation)Anthropic Claude + Web searchFacility name, location
  • Data sent is not used to train AI models (in accordance with the default policies of the Anthropic API and Google Cloud).
  • Numerical data (pH, temperature, component values) are values extracted by OCR from the original report, not generated or inferred by AI.
  • Explanatory text, catchphrases, and translations of indications are AI-generated, may differ from the original wording, and do not constitute medical advice. Such content is clearly marked with “AI-generated” or “machine translation” badges in the page.
  • If you find a clear error in the AI output, please contact us using the contact form.

4. Storage and Deletion

Collected personal information is retained for the duration of your account. An account deletion (withdrawal) feature will be implemented in stages. On withdrawal, we delete your email address, display name, and settings. Onsen analysis report data may be retained in anonymized form in consideration of the public interest.

5. Your Rights

You have the following rights (including for users to whom the GDPR applies).

  • Right of access (request disclosure of the personal data we hold)
  • Right to rectification (correction of inaccurate information)
  • Right to erasure (the “right to be forgotten”)
  • Right to restriction of processing and right to data portability
  • Right to object

To exercise these rights, please contact us using the contact form below.

6. Cookies and Tracking

The Service uses the following tools for access analytics. None of them send information that directly identifies an individual (such as name or email address).

  • Vercel Analytics (anonymized, cookie-free access analytics).
  • Google Analytics 4 (GA4, Google LLC). Aggregates trends in page views and actions (such as transitions to reservation sites) to improve the Service. GA4 uses cookies such as _ga to aggregate browsing activity and processes IP addresses with anonymization (configured not to store or record them). Individuals are not identified from the collected data.

GA4 measurement can be disabled by turning off cookies in your browser or by using the Google Analytics Opt-out Browser Add-on.

7. Minors

The Service is not intended for use by anyone under 13. For EU residents, use by anyone under 16 requires the consent of a parent or guardian.

8. Changes to This Policy

This policy may be revised as necessary. For material changes, we will notify you within the Service or by email.

9. Contact

For questions about personal information or to exercise your rights, please reach out via the contact form.