Privacy Policy

1. Introduction

SignCascade UD ("we", "us", or "our") respects the privacy of users of our "Shunkai App" (the "App") and is committed to protecting personal information. This Privacy Policy explains what information we collect and how we use it.

2. Information We Collect

We may collect the following information to provide and improve our services.

2.1 Information You Provide

• Email address when contacting us
• Survey responses
• Feedback and feature requests

2.2 Automatically Collected Information

Data Type	Purpose	Source
Device Identifier (Advertising ID)	Ad optimization	Google AdMob
Usage Data (screen views, session duration)	Service improvement & analytics	Firebase Analytics
Crash Logs	Bug fixes	Firebase Crashlytics
Device Information (OS, model)	Compatibility verification	Firebase
Purchase History	Billing management & support	Apple/Google

2.3 Locally Stored Information

The following information is stored only on your device and is not transmitted to our servers:

• Learning progress and scores
• App settings (theme, notifications, etc.)
• Study streak data

3. How We Use Information

We use the collected information only for the following purposes:

1. Providing and maintaining the App's functionality
2. Bug fixes and service improvements
3. Responding to inquiries
4. Displaying advertisements (free version only)
5. Creating usage statistics and analysis
6. Notifying about new features and updates

4. Disclosure to Third Parties

We do not disclose your personal information to third parties except in the following cases:

• With your consent
• When required by law
• When necessary to protect life, body, or property

4.1 Third-Party Services We Use

Service	Provider	Purpose	Privacy Policy
Firebase Analytics	Google LLC	Usage analytics	Link
Firebase Crashlytics	Google LLC	Crash analytics	Link
Google AdMob	Google LLC	Ad delivery	Link

5. Data Storage Location

• Your Device: Learning progress, settings (available offline)
• Google Firebase (United States): Usage statistics, crash logs
• Our Servers (Japan): Inquiry content, survey responses

6. Data Retention Period

• Usage statistics: 14 months from collection
• Crash logs: 90 days from collection
• Inquiry content: 3 years after resolution

7. Your Rights

You have the following rights:

• Right of Access: Request disclosure of collected personal information
• Right of Rectification: Request correction of inaccurate information
• Right of Erasure: Request deletion of personal information
• Opt-out: Reset or disable advertising ID in device settings

8. Advertising

The free version of the App displays advertisements through Google AdMob. Your advertising ID may be used to deliver interest-based advertisements.

If you do not wish to receive personalized ads, you can limit ad tracking in your device settings.

9. Children's Privacy

The App is intended for users aged 13 and older. We do not knowingly collect personal information from children under 13. If we discover that personal information from a child under 13 has been collected, we will promptly delete it.

10. Security

We implement appropriate technical and organizational measures to protect your information from unauthorized access, loss, or disclosure. However, no internet transmission is completely secure, and we cannot guarantee 100% security of your information.

11. Changes to This Policy

We may update this Privacy Policy as necessary. If there are significant changes, we will notify you within the App. Continued use of the App after changes constitutes acceptance of the revised policy.

12. Contact Us

For questions or comments about this Privacy Policy, please contact us at: