Terms of Use — Ninefold for Android

Using Ninefold

Ninefold is provided by Liang Lu (Gentleflow) for personal Sudoku play. Use the app lawfully and respect applicable intellectual-property rights. The game is for entertainment; its statistics and “brain profile” are gameplay feedback, not medical assessments or a promise of cognitive improvement.

Free play and Premium

The app includes free puzzle play, daily challenges and Hell Mode. Optional Premium features include choosing freely among 25,000 Campaign levels, unlimited Campaign hints and mistakes, automatic candidate notes, advanced statistics and additional themes. Hell Mode retains its challenge rules for everyone: five lives per run, without hints or automatic notes. Features and availability are described in the app.

Payments and subscriptions

Purchases are billed by Google Play in the currency and at the price displayed before confirmation. Monthly and yearly plans renew automatically for the selected billing period until canceled. If an eligible free trial is offered, Google Play displays its length, renewal price and billing period before you confirm. Unless you cancel before the trial ends, it converts to the paid subscription shown. Trial eligibility is determined by Google Play. A lifetime plan is a one-time purchase of the app’s Premium entitlement and has no recurring subscription charge.

You can manage or cancel subscriptions in Google Play under Payments & subscriptions. Cancellation normally stops the next renewal while access continues through the period already paid for, subject to Google Play’s applicable rules. Uninstalling Ninefold or clearing its data does not cancel a subscription. Refunds and statutory withdrawal rights are governed by applicable law and Google Play’s policies; nothing here limits mandatory consumer rights.

Restore and availability

Use Restore in the app with the Google Play account used to purchase. Google Play and RevenueCat validate access, so purchases and restoration require a network connection. Offline access may rely on previously verified membership. Purchases on another platform are not automatically transferred to Android. “Lifetime” describes a non-expiring entitlement for the supported app, not a guarantee that the app or third-party platforms will operate forever.

Your progress and responsibility

Keep your device and any enabled system backups secure. We aim to maintain a reliable game but cannot guarantee uninterrupted service or that local progress will survive device loss, deletion or software faults. To the extent permitted by law, the app is provided as available; legally required warranties and remedies remain unaffected. We may update features and these terms, showing the effective date on this page.

Privacy and contact

Read the Android privacy policy. For purchase, technical or legal support, email gentleflowoverseas@gmail.com.