Effective: 20 August 2026 / Last updated: 20 August 2026
Note on language. The Japanese version of these Terms is authoritative. This English translation is provided for convenience; if the two differ, the Japanese text governs.
These Terms set out the conditions for using GRND (the "App"). Anyone who uses the App (the "User") is deemed to have agreed to these Terms.
This app is not a medical device. The sleep and study records and the scores it displays are reference information to help you look back on your habits. They are not intended to diagnose, treat, or prevent any illness. If you have concerns about your sleep or your health, consult a doctor rather than relying on what this app shows.
1. Scope
These Terms apply to every aspect of the relationship between the User and the operator concerning use of the App. Any specific notices the operator posts inside the App or on these web pages form part of these Terms.
2. Accounts
Using the App requires an account. You can register with an email address and password, with an Apple ID, or with a Google account.
Registering an account lets you sync your data across multiple devices.
The User is responsible for managing their own credentials. They must not let a third party use them, or lend or transfer them.
The User can delete their account from inside the App at any time. Deletion permanently removes the cloud account and all associated data; it cannot be restored.
3. Fees
The current version of the App is provided free of charge.
Some features may be offered for a fee in future. If so, the price and what it covers will be shown before purchase.
Where paid features exist, payment and refunds follow Apple's rules. Refund requests should be made to Apple.
4. Prohibited conduct
When using the App, the User must not:
Act in violation of laws or public order and morals
Damage or interfere with the App's servers or network
Tamper with or reverse-engineer the App (except as permitted by law)
Access, or attempt to access, another User's account or data without authorisation
Place load beyond ordinary use through automated means
Infringe the rights of the operator or of a third party
5. Handling of data
The data the User records in the App (sleep, study, to-dos, goals, diary) belongs to the User. The operator will not use it for any purpose other than providing the App's features.
Handling of personal information is set out in the Privacy Policy.
The App is not a medical device and does not provide medical advice, diagnosis, or treatment. The scores, charts, and suggestions it shows are reference information derived from what the User entered. Consult a healthcare professional for decisions about your health.
The operator does not warrant that the App is free from defects in fact or in law.
The operator is not responsible for data loss caused by device failure, OS updates, communication problems, or failures of external services.
Except in cases of the operator's intent or gross negligence, the operator is not liable for damage arising from use of the App.
The above does not apply where liability cannot be excluded under the Consumer Contract Act or other mandatory provisions of law.
7. Changes, suspension, and termination of the service
The operator may change the App's content or suspend its provision without prior notice to the User.
If provision of the App ends, notice will be given on this page in advance where possible. The operator will endeavour to allow a reasonable period so that copies of data can be provided before the service ends.
8. Changes to these Terms
The operator may change these Terms when it judges this necessary. Amended Terms take effect when posted on this page. Continuing to use the App after a change is deemed acceptance of that change.
9. Governing law and jurisdiction
These Terms are interpreted and applied under the laws of Japan. In the event of a dispute concerning the App, the court with jurisdiction over the operator's address shall be the exclusive court of first instance by agreement.