Terms of Use

Kuzushi · version 1.5 · last updated September 25, 2026

What you get

Kuzushi is an educational app for recognizing casual spoken Japanese — hearing 食べちゃった and knowing it is 食べてしまった. Levels 1 and 2 are free in full. A single non-consumable in-app purchase — Kuzushi Premium — unlocks levels 3, 4 and 5 and covers material added to the levels later. Sessions aimed at your weak spots and practice of your weakest spots work without a purchase.

Version 1.5 adds a separate, optional feature: the “Sentences” tab with an “AI” badge, in which a language model turns a line you heard into its full form, without contractions (“Full form”), or shows how your own sentence is shortened in speech at levels 1, 3 and 5 (“As spoken”). It is paid for with the subscription described below.

Purchases and refunds

The app is licensed under Apple's standard licence terms (Licensed Application End User License Agreement). These terms supplement them and cover what applies to Kuzushi only; where the two conflict, Apple's terms prevail.

Purchases are processed by Apple under the App Store terms. Refunds are handled by Apple, not by the developer — request one at reportaproblem.apple.com. “Restore purchases” re-checks your entitlements on any device signed in with the same Apple Account.

AI Help — auto-renewing subscription

The “Sentences” tab is the only part of the app that costs money every time it is used, which is why it is sold as a subscription rather than a lifetime purchase.

Everyone gets a free sample every month — currently 5 requests — with or without Premium and without a subscription. The app shows how many are left and when they come back.
An empty answer — when a line has no contraction to expand or no pattern fits a sentence — does not use up a request from your allowance.
More requests come with the AI Help subscription, monthly or yearly. The app shows the price and the period before you buy, in your currency. The subscription has a daily and a monthly request limit that protects the service from abuse.
The subscription renews automatically until you turn it off. The charge for the next period is taken from your Apple Account within 24 hours before the current period ends.
Cancelling: in your Apple Account settings (Settings → your name → Subscriptions) or with the Manage subscription button in the app, at least 24 hours before the current period ends. The subscription keeps working until the end of the period you paid for.
The subscription does not unlock levels 3–5, and Kuzushi Premium does not include the subscription. They are two separate products; material bought once stays yours regardless of the subscription.
The “Sentences” tab needs an internet connection and may be temporarily unavailable — during maintenance, for example, or an outage at the model provider. The rest of the app keeps working normally.

The learning content

The patterns, example sentences, translations and explanations are original work and are provided for personal study. They may not be reproduced, redistributed or used to train machine-learning models.

Casual speech is not one fixed thing. It varies with region, age, who you are talking to and how well you know them, and it changes faster than written Japanese does. Kuzushi teaches the standard, widely understood forms and marks which of them are polite and which are not — but judging whether a given situation calls for one is yours to do, not the app's. The five levels describe how the material is ordered for learning; they are not examination levels, and the app is not affiliated with, authorized by or endorsed by any body that administers a Japanese-language examination.

Answers in the “Sentences” tab

The full form of a line and the rendering of a sentence as spoken are generated by a language model, and they can be wrong — including on points native speakers disagree about, and a line lifted out of a dialogue can be ambiguous without its context. Treat the answer as a starting point to check, not as a tutor's opinion or an exam grade. It does not count towards your progress or your practice.

No warranty

The app is provided "as is". While the content is checked carefully and validated automatically, no guarantee is given that it is free of error. The developer is not liable for damages arising from its use. This does not limit any consumer rights under mandatory law.

Your data is your responsibility

Progress is stored on your device only. Use "Export progress" in Settings if you want a copy; importing one replaces everything on the device it is imported into. Deleting the app deletes your progress with it. The exception is the “Sentences” tab, and only when you tap the button yourself: the line you typed is sent to the server. What exactly is kept, and for how long, is set out in the privacy policy.