Privacy Policy

Kuzushi · version 1.0.0 · last updated 4 September 2026

Short version: Kuzushi collects nothing. It has no account, no analytics, no advertising and no server. The app makes no network request of any kind except to the App Store, for the purchase itself.

Your account

There isn't one. Kuzushi does not ask you to register, sign in or provide an email address, and it has no way to identify you.

Where your learning data goes

Nowhere. Your mastery of each pattern, your answer history and your session history are stored on your device and never leave it. If you export a backup, the resulting file is yours — it is written wherever you choose to save it, and the app does not upload it.

Data shared with the developer's other apps

Kuzushi belongs to a family of Japanese-learning apps, alongside Kaname (grammar), Katsuyokei (conjugation), Joshi (particles), Kazoekata (counters) and Bunmyaku (reading). If you have more than one of them installed, the home screen shows a Your Japanese section with one row per app.

Here is how that works: Kuzushi writes a small card file on your device, in an area shared by the apps in this family. The card carries six things about your studying: how much of the material you have mastered, how many days your streak runs, how many sessions you have done, one sentence about your weakest spot (in Polish and in English), whether today's goal is already met, and when your next reviews fall due. Plus three technical ones: which app wrote the file, in what format, and when. Nothing else. There is no answer history and no list of the items you practiced, and your progress cannot be reconstructed from this file.

The file never leaves your device, and it is read only by the other apps in this family that you have installed on that same device. There is no server and no account here, and nothing syncs between devices.

Two things worth saying plainly. First, the shared area survives uninstalling a single app — the file goes only once you remove every app in the family from the device. Second, “Erase all progress” deletes this file too, along with everything else.

Reminders

The evening reminder is optional and entirely local. If you turn it on, iOS schedules the notification on the device; nothing is sent anywhere and no server is involved. If you decline the notification permission, the rest of the app works exactly as before.

Tracking and advertising

None. There is no analytics SDK, no advertising SDK, no crash reporter and no tracking identifier of any kind in the app.

Purchases

The one-off Premium purchase is handled entirely by Apple. Kuzushi never sees your payment details; it only asks StoreKit whether a purchase exists.

Reporting a problem

If you use "Report a problem" in Settings, your mail app opens with a message you can read and edit before sending. It includes the app version, the build number, the iOS version and the device model series — never a device identifier. You can delete those lines before sending.

Children

Kuzushi is rated 4+ and collects no data from anyone, of any age.

Changes

If this policy ever changes, the updated date at the top changes with it.