Privacy Policy

1. Registered account information: email address and username. Passwords are encrypted and stored by the authentication service; we cannot see them.
2. Guest (not logged in) information: a temporary account ID for each device and browser, and a name like “ゲスト-xxxxxx” (Guest-xxxxxx). We do not collect names or email addresses.
3. Play records: problems opened, time played, clear times, rating, answers (the nets you drew and the folding steps), contest results, and the contents of problem submissions.
4. Class (Classroom Plan) information: the class name, school or classroom name, and how the teacher found the Service (entered by the teacher); nicknames entered by students; join dates and times; and assignment progress.
5. Access information: a random number for each device, pages viewed, referrer, device type, device information such as OS, browser, screen size, and language, and login dates and times.
6. Inquiry information: the contents of your inquiry, your reply email address, and any attached photos.

1. To provide the Service (saving records, timing, showing rankings and contests, transferring guest records to an account, etc.)
2. To show teachers their students’ progress in the Classroom Plan
3. To check for invalid records and prevent misuse
4. For aggregation and analysis to improve the Service (which pages are viewed most, which problems are hard, etc.)
5. To reply to inquiries and to send notices about Classroom Plan payments and deadlines

The following information is visible to other users within the Service:

1. Usernames (guests appear as “ゲスト-xxxxxx”), ratings, and times shown in rankings, contest standings, and profile pages
2. Nicknames and records shown in class rankings (visible only to the teacher and students of the same class)
3. A class’s teacher can see the nicknames, play records, and last played dates of students in that class

Please do not use your real name as your username or nickname.

We do not share user information with other people or companies, except:

1. With the user’s consent
2. When required by law
3. When necessary to protect a person’s life, body, or property and it is difficult to obtain the user’s consent

The Service uses the following external services. Information is stored on the servers of these services (including servers located outside Japan).

1. Supabase: database and login system
2. Vercel: site delivery and access analytics (Vercel Analytics)
3. Payment services (such as PayPal): Classroom Plan payments. Card numbers are handled by the payment service; we do not receive them

The Service is operated from outside Japan.

We store your login state, guest temporary account, language setting, problems cleared on this device, and similar data in your browser’s storage (such as local storage). We do not track you for advertising.

The Service is also used by children, such as elementary school students. Children should sign up or join a class with the permission of a parent, guardian, or teacher. Teachers should ask students to use a nickname, not their real name.

We keep information for as long as needed to provide the Service. Access information and inquiries are deleted once they are no longer needed.

If you would like to view, correct, or delete your information, or ask us to stop using it, please contact us via the contact form. After confirming that you are the person concerned (or their parent or guardian, for children), we will respond promptly. To delete guest records, please tell us the guest name (ゲスト-xxxxxx).

To prevent unauthorized access to or loss of information, we take measures such as limiting database reads and writes to what is necessary.

When we change this policy, we will announce it within the Service.

Kyoten Operations Office　Contact form