Terms of Use

1. The service

Tokkun is a Japanese-language practice tool provided by Nixlight. It offers curated drill content, flashcard and input modes, audio playback, spaced repetition scheduling, progress tracking, and related study features. Tokkun is a practice aid, not a complete language course, official test provider, certification service, or professional educational adviser.

2. License and acceptable use

Subject to these terms and the rules of the store from which you obtained Tokkun, we grant you a limited, personal, non-exclusive, non-transferable, revocable license to use the app for lawful, non-commercial purposes.

You must not:

• copy, redistribute, sell, sublicense, or commercially exploit the app or its content except where law expressly permits;
• reverse engineer, bypass security, interfere with operation, or access the app in an unauthorized manner;
• use Tokkun to violate law, infringe rights, or harm another person or service;
• misrepresent your relationship with Nixlight or Tokkun.

3. Free credits and rewarded ads

The free version may provide an initial credit balance. Each practiced card consumes one credit. You may choose to watch a completed rewarded ad to earn additional credits, subject to a daily limit and ad availability. Credits have no cash value, cannot be transferred, and are not redeemable outside Tokkun. We may adjust free-credit amounts, reward amounts, daily limits, or availability to maintain and improve the service.

4. Lifetime Premium

Lifetime Premium is a one-time in-app purchase that unlocks the premium features identified in the app for the supported lifetime of Tokkun. It is not a subscription and does not guarantee that every current feature, operating system, device, or third-party service will remain available forever.

Purchases, billing, family sharing where available, cancellations, and refunds are handled by Apple App Store or Google Play under their terms. You can use the app’s restore function to request restoration for an eligible purchase associated with your store account.

5. Content and corrections

We work to make Tokkun’s Japanese content accurate and useful, but language has variants, context, and occasional ambiguity. We do not warrant that all entries, readings, translations, conjugations, examples, audio, schedules, or explanations are complete or error-free. The “Found an error” action and support@nixlight.com are available for corrections. We may revise, add, retire, or reorganize content in updates.

6. Learning results

Spaced repetition schedules are estimates based on your ratings and app settings. Learning outcomes vary by person, consistency, prior knowledge, and other factors. Tokkun does not promise a particular score, proficiency level, memory result, or examination outcome.

7. Your data and device

Tokkun stores learning data locally. You are responsible for maintaining access to your device and any platform backups you choose to use. Removing the app, clearing app data, losing a device, or changing platform behavior may result in loss of local progress. Our handling of information is described in the Privacy Policy.

8. Third-party services

Tokkun relies on services provided by Apple, Google, RevenueCat, Cloudflare, device text-to-speech providers, and other platform components. Their terms and policies may apply separately. We are not responsible for outages, decisions, changes, or content controlled solely by those third parties.

9. Availability and changes

We may update, modify, suspend, or discontinue parts of Tokkun to fix errors, improve the product, meet legal or store requirements, or respond to changes in supported platforms and third-party services. We will make reasonable efforts to avoid unnecessary disruption, but continuous availability is not guaranteed.

10. Intellectual property

Tokkun, its software, design, original data organization, branding, and associated materials are owned by Nixlight or its licensors and are protected by applicable intellectual-property laws. Japanese words and grammatical facts are not claimed as proprietary merely by appearing in the app.

11. Disclaimers

To the maximum extent permitted by law, Tokkun is provided “as is” and “as available,” without warranties of merchantability, fitness for a particular purpose, non-infringement, accuracy, or uninterrupted operation. Nothing in these terms excludes rights or warranties that cannot lawfully be excluded.

12. Limitation of liability

To the maximum extent permitted by law, Nixlight will not be liable for indirect, incidental, special, consequential, or punitive damages, or for loss of progress, data, opportunity, revenue, or expected learning results arising from your use of Tokkun. Where liability cannot be excluded, it will be limited to the amount you paid for Tokkun in the twelve months before the event giving rise to the claim, unless applicable law requires otherwise.

13. Termination

You may stop using Tokkun at any time. We may restrict use if you materially violate these terms or if necessary to protect the app, users, rights, or legal compliance. Provisions that by their nature should survive termination will continue to apply.

14. Governing terms and changes

These terms are governed by applicable law, without overriding mandatory consumer protections available where you live. We may update the terms as Tokkun changes. The effective date above identifies the current version. Continued use after an update means you accept the revised terms where permitted by law.