privacy policy

Privacy Policy

Last updated: August 30, 2026

This policy describes how information is handled in the following iOS apps, developed and provided by Shuntarou Kojima (the "Developer").

Apps covered by this policy, and the external services they use

- ChemiMaster

  Uses Firebase Authentication, Cloud Firestore, Game Center, and the iCloud key-value store.

- Remove The Impurities

  Uses Game Center only. It does not use Firebase.

Both apps are provided free of charge. Neither displays advertising, and neither performs tracking for advertising purposes.

Some sections of this policy apply to only one of the apps. Each section indicates which apps it covers.

1. Information We Collect

(a) Usage Information  [both apps]

Neither app collects usage statistics such as launch counts, screen transitions, or feature usage counts. ChemiMaster includes Firebase SDKs provided by Google LLC, but Firebase Analytics is disabled.

We do not collect your name, address, phone number, email address, or date of birth.

(b) Information Related to Rankings  [ChemiMaster only]

If you use ChemiMaster's ranking features, the following information is stored using Firebase Authentication (anonymous sign-in) and Cloud Firestore, both provided by Google LLC:

- An anonymous authentication ID: a random identifier generated by the app. It is not linked to your Apple ID or to any other personal information.

- A display name: if you are signed in to Game Center, ChemiMaster uses your Game Center nickname (adjusted to a maximum of 10 characters for display and storage in the app). If you are not signed in, the app uses its default display name.

- The ID of the avatar you have selected

- Your scores and the times they were updated

Please note:

Your display name, avatar, and scores are shown publicly to other users on the ranking screens. Do not use your real name, email address, school name, or anything else that could identify you or another person as your display name. Your display name is your Game Center nickname. To change it, open your device's Settings, go to Game Center, and then tap the Sync button on the app's settings screen to apply the new name. If you are not signed in to Game Center, the display name stays as the default and no name you have entered is sent.

(c) Information Related to Game Center  [both apps]

If you use either app while signed in to Apple's Game Center, your Game Center nickname and scores are sent to Apple Inc.'s servers and shown on the leaderboards. Information handled within Game Center is subject to Apple Inc.'s privacy policy. If you do not use Game Center, no such data is sent.

Your Game Center nickname is visible to other users. You can set and change it from Apple's Game Center settings.

(d) Information Stored on Your Device and in iCloud  [ChemiMaster only]

Your progress, the items you have obtained, and your settings are stored on your device. If you are signed in to iCloud, selected data is automatically backed up to Apple's iCloud key-value store and may be restored after you reinstall the app or on another device using the same Apple Account. Deleting the app removes ordinary data from the device, but the iCloud backup may remain.

To prevent improper data restoration, the app also stores an app-generated device identifier and cumulative consumption counts for applicable items in the device Keychain. This information may remain on the same device after the app is deleted.

(e) Information Stored on Your Device  [Remove The Impurities only]

Progress and settings for Remove The Impurities are stored on your device and are erased when you delete the app.

2. How We Use Information

We use the information collected solely for the following purposes:

- To provide the apps' features, including rankings

- To back up and restore ChemiMaster data through iCloud

- To prevent item consumption from being reversed using an older backup

- To identify and fix problems

We never use this information for advertising, for tracking for advertising purposes, or for sale or rental to others. Neither app uses the Advertising Identifier (IDFA), and neither requests App Tracking Transparency permission.

3. Third Parties and Service Providers

We use the following services to accomplish the purposes above. These providers handle information only within the scope of the work the Developer has designated.

- Google LLC  [ChemiMaster only]

  Services used: Firebase Authentication, Cloud Firestore

  Privacy policy: https://firebase.google.com/support/privacy

- Apple Inc.  [both apps]

  Services used: Game Center; iCloud key-value store (ChemiMaster only)

  Privacy policy: https://www.apple.com/legal/privacy/

We do not provide your information to any third party other than those listed above.

4. International Data Transfers  [ChemiMaster only]

Firebase servers are located outside Japan, primarily in the United States. The information described in section 1(b) is transmitted to and stored on those servers. By using ChemiMaster, you consent to this transfer.

The iCloud backup described in section 1(d) is processed and stored in accordance with Apple Inc.'s privacy policy and the terms applicable to iCloud.

5. Retention and Deletion

- Data on your device [both apps]

  Deleting the app removes ordinary app data stored on the device. However, ChemiMaster's anti-restoration information may remain in the Keychain on the same device.

- iCloud backup [ChemiMaster only]

  The backup may remain in iCloud after the app is deleted and may be restored after reinstallation. The Developer cannot remotely view or delete an individual user's iCloud backup. To stop syncing, turn off iCloud access for ChemiMaster in your device's iCloud settings.

- Ranking data in Cloud Firestore [ChemiMaster only]

  Retained until you ask us to delete it. To request deletion, contact us through the channel in section 9. We may ask you for the ID shown on the app's settings screen in order to identify your record.

- Game Center data [both apps]

  You can delete this yourself from Apple's settings.

6. Security

We use the security measures provided by Firebase and Apple services. ChemiMaster's Cloud Firestore is also configured with security rules so that users cannot modify records other than their own.

However, no method of transmission over the Internet or of electronic storage is completely secure, and we cannot guarantee absolute security.

7. Children

Both apps carry a 4+ age rating. The Developer does not collect information that would reveal a user's age.

As described above, the Developer does not collect personally identifying information. However, ChemiMaster's ranking display name and your Game Center nickname are entered by you and are shown publicly to other users. If a child uses either app, please advise them not to enter their real name, school name, or similar details.

If you believe a child's information has been stored unintentionally, please contact us using the channel below and we will delete it promptly.

8. Cookies and External Links

Neither app uses web browser cookies.

The apps may contain links to external websites. The Developer is not responsible for how those sites handle information. Please review the privacy policy of each site you visit.

9. Contact

For questions about this policy, or to request deletion or disclosure of your data, please contact us using the form below.

Contact form:

https://docs.google.com/forms/d/e/1FAIpQLScUfeoIKbXASKJMLYpM0SkqIBKU5eOr7ywFtbgQ0BzZ35bOTA/viewform

In ChemiMaster, you can reach the same form from within the app at "My Page > Settings > Support > Contact".

10. Changes to This Policy

We may revise this policy as needed. If we make a significant change, we will post the revised text and the updated date on this page. Revisions take effect when they are posted here.