Privacy Policy

1. Information We Collect

This site may collect the following information:

・Email address (at registration)

・Display name (at registration, optional)

・Learning history (questions answered, correctness, response time)

・Google account information (only when Google login is used)

・AI consultation content (your questions and the answers when you use the "Ask AI" feature)

2. Purpose of Use

The collected information is used for the following purposes:

・Managing and displaying learning history

・Sending password reset emails

・Operating and improving the service

・Preventing unauthorized access

・Generating answers and displaying history for the "Ask AI" feature

3. Provision to Third Parties

We do not provide collected personal information to third parties except as required by law.

However, when you use the "Ask AI" feature, the content you enter is sent to Anthropic, PBC within the scope described in "4. Use of Generative AI (Claude)" below.

4. Use of Generative AI (Claude)

The "Ask AI" feature on this site uses the API of "Claude", a generative AI provided by Anthropic, PBC (United States).

The following information is sent to Anthropic only when you press the send button in this feature. No other action sends information.

・The question you entered

・The quiz questions being discussed (question text, choices, correct answer, your answer, explanation), or the vocabulary, grammar patterns or idioms you are studying together with their explanations and examples

・The language to answer in (your display language)

Account information such as your email address, display name or user ID is not sent. Please do not write personal information such as your name or contact details in your question.

Anthropic states that it does not use content sent through its API to train its models. For details on how Anthropic handles data, please see Anthropic's Privacy Policy.

Your questions and the answers are stored on this site's server as history and shown again on the result screen and My Page. You can delete the history from My Page. After deletion, a usage record without the text (date and time, number of questions, character counts, etc.) is kept to manage usage limits.

AI answers are generated automatically and may contain errors.

5. Use of Cookies

This site uses browser cookies and temporary session storage for the following purposes:

・Saving language settings

・Maintaining login state (JWT token)

・Recording your acceptance of the disclaimer

・Saving display settings (number of quiz questions, selected question range, view mode, display time zone, etc.)

・Temporarily holding data for a quiz in progress (cleared when the browser tab is closed)

If you disable cookies in your browser settings, some features may become unavailable.

6. Access Analysis and Advertising

This site uses Google Analytics (GA4) to understand access trends. Google Analytics uses cookies to collect and analyze usage data. The collected information is aggregated anonymously and does not identify individuals. For details, please see Google's Privacy Policy.

In addition, this site is considering introducing Google AdSense in the future. If introduced, this policy will be updated accordingly.

7. Data Retention and Deletion

Data of registered users is retained until you delete your account or the service ends. You can delete your account from My Page. There is a 30-day grace period after deletion during which the account can be restored; after that, the data is permanently deleted. Usage records of the Ask AI feature remain only as anonymous aggregate data no longer linked to a user.

Ask AI history can be deleted item by item from My Page.

If you use the site without registering, no learning history is stored on the server or in your browser.

If you cannot delete your account from My Page, please contact us via the form listed in the "Contact" section at the bottom of this page.

8. Security

Passwords are hashed with bcrypt before storage. We never store plaintext passwords on the server.

9. Changes to This Policy

This policy may be changed without notice. If there are significant changes, we will announce them on the site.

10. Contact

For inquiries regarding personal information, please contact us via the contact form. For details about the operator, please see Operator Information.