Privacy Policy

Last updated: September 15, 2026

HK-MJ-CTR ("the app") is designed to work entirely on your device. This policy explains exactly what data the app handles and, just as importantly, what it does not do.

Summary

• The app does not have user accounts or sign-in.
• The app does not use analytics, tracking, or advertising SDKs of any kind.
• The app does not make network requests. It works fully offline.
• Nothing you enter or photograph is ever uploaded, transmitted, or shared with us or anyone else.

What the app stores, and where

All data below is stored only in the app's local storage on your device (in its sandboxed Documents folder), using Apple's standard on-device storage APIs. None of it leaves your device.

• Game data: player names, scores, round history, and scoring rules you configure.
• Photos of winning hands: when you photograph tiles for recognition, that photo is processed on-device using Apple's Vision framework to detect tile shapes. A small cropped image of each tile you confirm is saved locally so future recognition attempts can compare against your own physical tile set — this is the app "learning," and it happens entirely on your device.
• Event photos: any photos you choose to attach to a game (e.g. of the table or players) are stored locally, the same way.

Camera and Photo Library access

The app requests camera and photo library permission solely so you can capture or select a photo of a mahjong hand for tile recognition, or attach a photo to a game. These permissions are never used for any other purpose, and no photo is transmitted anywhere.

Deleting your data

Deleting a game from within the app also deletes its associated photos and reference data. Deleting the app from your device removes all of its data, since nothing is stored anywhere else.

Children's privacy

The app does not knowingly collect any personal information from anyone, including children, because it does not collect or transmit personal information at all.

Changes to this policy

If this policy ever changes — for example, if a future version of the app adds an optional feature that involves network access — this page will be updated and the "Last updated" date above will change accordingly.

Contact

Questions about this policy can be sent to admin@tsunagu.ch.