Privacy Policy

隐私政策

Last Updated: October 2026

1. Data that stays on your device

The following is stored locally using the Hive database and is never uploaded:

• Learning progress: unlocked chapters, completed levels, current position
• Quiz statistics: accuracy, total questions answered, per-chapter stats
• Study records: study days and current streak
• Wrong answers: IDs of questions you got wrong, for review
• App settings: theme, language, font size, AI tutor switch

2. Data that leaves your device

To show ads, fix crashes, and learn which lessons need work, the app sends data to these services:

• Google AdMob (advertising): advertising ID, device identifiers, and approximate location (inferred from IP, not GPS). This is shared with Google to serve and measure ads. Buying the ad-free upgrade stops ads being shown.
• Firebase Crashlytics (crash reporting): crash stack traces, device model, OS version, app version — used to find and fix crashes.
• Firebase Analytics (usage statistics): anonymous interaction events, such as which chapter was opened and how many questions were answered — used to decide which lessons need improving.
• In-app purchases: handled by the app store you installed this app from when you buy the ad-free upgrade. Your card and bank details never reach us; the store returns only a purchase record — which product, and whether it succeeded — which the app uses to unlock and restore the upgrade.
• AI tutor (optional, off by default): see the next section.

3. The AI tutor (optional, off by default)

What gets sent

• The text you type into the chat
• The question or lesson you are asking about (its text, options, correct answer, explanation, and which answer you picked)
• Your app language setting, so the reply comes back in your language
• An anonymous installation identifier, used to count your questions per day

Where it goes

To our server on Google Cloud, and from there to Google Vertex AI (Gemini models) to generate the reply. Google acts as our service provider here, processing the data on our behalf. It is not used to train models.

What we keep

• We do not store your conversations. A conversation exists only while the app is open and is gone when you close it. Our server never writes your message text down.
• We keep a per-day counter tied to that anonymous identifier, to enforce the daily question limit.
• We record an anonymous signal — which lesson a conversation was about, and whether the learner said the answer looked wrong — with no identifier and no message text attached. This is how we find questions we got wrong.

What you should know

• Replies are AI-generated and can be wrong. Please don't treat the tutor as an authoritative rules ruling.
• Please don't type personal information into the chat — the feature doesn't need it and we don't want to receive it.
• There is a daily limit on questions, which resets the next day.

4. About your identity

The app has no account system and never asks for your name, email address, password, or phone number. The anonymous identifier described above is generated automatically on the device, is used only for counting, and does not point to a person. Reinstalling the app produces a brand-new identifier that cannot be linked to the old one.

Optional email list. The More Games screen, and the certificate you get after the last chapter, link to a Google Form where you can choose to get a short email when we release a new app (at most once a month), join the Riichi Dojo test group (an email only when we are about to build something new, or have a test build for you), or both. The app sends nothing to the form: it opens in your browser, and only what you submit there is kept. We keep the email address of the Google account you sign in with, the options you ticked, where you found the form, and when. We also keep a record of each email we send you (address, subject and date), and test-group members are on the app’s tester list while they are in the group. Your entry is kept until you leave; the record of emails sent stays after you leave, with no end date, so we can show what we sent and to whom (our legitimate interest). Leaving does not affect emails sent before you left. Google hosts the form and our email, GitHub holds a private backup of our send records, and test builds go through the app store’s own testing service. Google and GitHub are US companies, so this data may be stored outside your country; both are certified under the EU-U.S. Data Privacy Framework and its UK and Swiss extensions (details at dataprivacyframework.gov). We use the list only to send what you signed up for, and never sell your address or share it for anyone else’s marketing. To leave, reply “stop” to any email, or write to studio.peach.go+news@gmail.com, and we delete your entry and take you off the tester list. If you joined a test build through a public link, also leave it in the testing app: that list does not show us who you are.

5. Data we do not collect

• Name, password, phone number, postal address
• Email address, unless you sign up for the optional email list (section 4)
• Contacts, calendar, SMS messages
• Photos, videos, audio, or files on your device
• Precise (GPS) location
• Health, financial, or biometric information

6. Deleting your data

• Local data: uninstall the app, or use Settings → Apps → Riichi Dojo → Clear Data. All learning records are permanently deleted immediately.
• Stop sending: switch the AI tutor off in Settings and nothing further leaves your device.
• Server-side data: email studio.peach.go+riichi@gmail.com to request deletion of the counter associated with your anonymous identifier.
• Email list: reply “stop” to any email, or write to studio.peach.go+news@gmail.com, and we delete your entry and take you off the tester list (if you joined a test build through a public link, also leave it in the testing app). The record of emails already sent stays.
• Ad personalisation: reset or delete your advertising ID under Settings → Google → Ads on your device.

Note: Data cannot be recovered after deletion. Please confirm before proceeding.

7. Children's privacy

Riichi Dojo is a general-audience app. It is not directed at children under 13, and we do not knowingly collect personal information from children. If you believe a child has provided us with personal information, please contact us at the address below and we will delete it.

8. Third-party privacy policies

• Google (AdMob, Firebase, Vertex AI, Forms): policies.google.com/privacy
• App store billing: governed by the privacy policy of the app store you installed this app from.
• How Google uses advertising data: policies.google.com/technologies/partner-sites

Note: The app may contain external links (reference material or feedback pages) which open in your browser and are not controlled by this app.

9. Privacy policy updates

We may update this policy from time to time. Significant changes are reflected in the "Last Updated" date at the top of this page. We recommend reviewing it periodically.

10. Contact us

11. Your rights

Under applicable privacy regulations you have the following rights:

• To be informed: this page lists everything that leaves your device.
• Access: your learning data and statistics are viewable in the app at any time.
• Deletion: see section 6.
• Choice: the AI tutor is off by default and can be switched off again at any time.