Privacy Policy (Mahjong Score Memo)

Effective Date: February 22, 2026

Last Updated: February 22, 2026

Hiroshi Oda ("we," "us," or "our") provides the smartphone application "Mahjong Score Memo" (the "App"). This Privacy Policy explains how we collect, use, and handle user information in connection with the App.

1. Information We Collect

We may collect or process the following categories of information through the App.

1-1. Authentication Information

Information provided through Google Sign-In (such as a Google account identifier, display name, email address, and other basic profile information)
User identifier (UID) issued by Firebase Authentication

The actual data received may vary depending on Google/Firebase configuration and the user's consent settings.

1-2. Information You Input and Store in the App

Player names
Match results (raw scores, ranks, total scores, seat positions, date/time, etc.)
Game information (game ID, status, start/end times, etc.)
League information (league name, participants, rule settings, etc.)
Custom rule settings
League sharing settings (share status, share ID, etc.)

1-3. Automatically Collected Usage / Diagnostic Information

The App uses the following services for quality improvement and troubleshooting:

Firebase Analytics (usage analytics)
Firebase Crashlytics (crash and error reporting)

As a result, device information, app usage data, crash logs, and diagnostic information may be automatically transmitted.

2. How We Use Information

We use collected information for the following purposes:

To provide the App, authenticate users, and manage sign-in
To provide App features such as score recording, statistics, history display, and league management
To separate and protect each user's data
To provide public league pages through the league sharing feature
To investigate issues, respond to failures, improve quality, and analyze usage trends
To prevent misuse and improve security
To respond to inquiries

3. Third-Party Services

The App primarily uses the following third-party services:

Google Firebase Authentication (authentication)
Google Cloud Firestore (data storage)
Firebase Analytics (analytics)
Firebase Crashlytics (crash reporting)
Cloud Functions for Firebase (e.g., syncing shared league data)

Please also review the following policies for more information:

4. Sharing and Public Disclosure

4-1. General Third-Party Sharing

We do not provide personal information to third parties without your consent, except as required by law.

4-2. Public Disclosure via League Sharing Links

The App includes a league sharing feature. If you enable sharing, anyone with the shared URL may be able to view certain league-related information on a public page, including:

League name
Ranking information (position, player names, total score, average rank, etc.)
Score trend data
Match records (date/time and player scores, etc.)

You can control whether sharing is enabled or paused. When sharing is paused, the public page is no longer displayed (subject to system processing delays).

5. Data Security

We take reasonable measures to protect collected information against unauthorized access, leakage, loss, or damage. The App is designed to separate user data and restrict access so that authenticated users can access only their own data.

However, no method of internet transmission or cloud storage is completely secure, and we cannot guarantee absolute security.

6. Data Retention and Deletion

Data you store in the App may be retained until you delete it.
The App includes a data deletion feature for match/league-related data.
Uninstalling the App may not immediately delete data stored in the cloud.
Logs and diagnostic information may be retained for a period required for legal or operational purposes.

7. Your Choices

Not sign in with Google (however, the App cannot be used without sign-in)
Not enable league sharing, or pause it later
Delete your data in the App
Uninstall the App

Depending on your device/OS, you may also be able to limit certain analytics-related settings.

8. Children's Privacy

The App is not primarily intended for children who require parental consent under applicable laws. If a user below the age of digital consent uses the App, they should do so with parental/guardian involvement.

9. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. If we make material changes, we will provide notice through the App, the distribution page, or another appropriate method. Unless otherwise stated, the revised policy becomes effective when posted.

10. Contact

If you have any questions about this Privacy Policy, please contact us:

Operator Name: Hiroshi Oda
Email: hi12801280@gmail.com

This page was prepared based on the app design specification (Google Sign-In, Firebase Auth / Firestore, Crashlytics / Analytics, and league sharing feature). Please update it as needed to match actual operations.