Privacy Policy (Android / iPhone app)

Last updated: September 29, 2026

This English version is a reference translation. The Japanese version is the governing text.

This policy applies to the smartphone app "Kotonoa Kanji" (the "App"). It does not cover the website (kotonoa.jp), which is governed separately. The App is designed for children and respects users' privacy as much as possible.

Learning data (stored on your device only)

Learning progress, settings, and similar data are stored only on your device. They are not automatically sent, synced, or backed up to our servers or any external cloud.

The App lets you export your progress data to a backup file and restore it yourself. Exporting and restoring use your device's file picker, and you manage where the file is saved, shared, or deleted. We never receive the contents of that file.

If you uninstall the App, the data stored in the App is deleted from your device (backup files you exported yourself remain where you saved them).

Information we do not collect

The App does not collect names, email addresses, phone numbers, postal addresses, location, contacts, photos, or advertising IDs (AAID / IDFA). We do not collect personal information from children.

Payments and subscription management

Payments for paid plans are processed through the App Store's billing system on iPhone and Google Play's billing system on Android.

The App uses RevenueCat for subscription management. Whether or not you make a purchase, mainly the following information is recorded at RevenueCat, linked to the Support ID that the App generates automatically (an ID that does not directly identify any individual).

• Information about the app and device environment (such as app and OS versions, and the device's language and region settings)
• The dates and times first and last recorded at RevenueCat, and the country (derived from the network connection; the IP address is not stored)
• If you purchase a paid plan: purchase information such as purchase and subscription history and status, currency, and store transaction ID

This information is used only to activate and restore purchases, prevent fraud, manage subscriptions, and improve the App. It is not used for advertising.

Network use

The App's learning features work offline. The App may use the internet to update or add content, and to check purchase and subscription status.

Advertising and tracking

The App shows no ads. We do not use behavioral targeting or remarketing. We do not use third-party analytics SDKs or tracking, and we do not collect advertising IDs (AAID / IDFA). Information recorded at RevenueCat is never combined with information from other apps or websites.

Children's privacy

The App is designed for children. In line with the Google Play Families Policy, the children's privacy provisions of the App Store Review Guidelines, and the spirit of COPPA (the U.S. Children's Online Privacy Protection Act) and GDPR-K (the EU GDPR provisions on children), we do not collect personal information from children. The Support ID and the information recorded with it at RevenueCat are used only for internal analysis to maintain and improve the service, and never to contact your child, for advertising, or to build profiles. Purchases are intended to be made by a parent (there is an adult check before purchasing).

Third-party services

The App uses the App Store (iPhone) and Google Play (Android) for payments, and RevenueCat for subscription management. Their processing is subject to each company's privacy policy. These services may process data on servers outside Japan (such as in the United States).

Google: https://policies.google.com/privacy

RevenueCat: https://www.revenuecat.com/privacy

Retention

We do not keep personal information such as names, email addresses, or phone numbers.

Learning progress, settings, and child profiles are stored only on your device and are deleted from the device when you delete the App (backup files you exported yourself remain where you saved them).

If you purchase a paid plan, the purchase record (Support ID, purchase and subscription history and status, and country at the time of purchase) is kept to manage subscription status, restore purchases, prevent fraud, and respond to inquiries. This record contains no personally identifiable information.

Even if you do not make a purchase, the information described in "Payments and subscription management" above (such as the date and time last recorded) is recorded at RevenueCat. It is kept to manage subscriptions and improve the App, and contains no information that directly identifies any individual.

Transaction records for purchases are held by Google Play / the App Store and cannot be deleted by us. Each store's policy applies.

Contact

For questions about this policy, please use our contact form.

For questions about purchases and subscriptions (for example, a purchase that has not been applied), please include your Support ID, shown under Settings → "For Parents" in the App (you can copy it), in the contact form. If your store also gave you an order number, please include that as well — note that the App Store does not issue one during a free trial.

Because we do not keep purchasers' names or email addresses, we confirm your purchase using the Support ID.

If a purchase does not appear after switching devices or reinstalling, please first try "Restore purchases" in the App.

Changes

We may revise this policy when features or services change, when laws change, or when we otherwise consider it necessary. When we revise it, we will post it on this page and in the App and update the "Last updated" date. The revised policy takes effect when it is posted. However, for changes that newly expand how children's personal information is handled, we will obtain parental consent before they apply, as required by law. If you continue to use the App after a revision, you are deemed to have agreed to the revised policy.