日本語

Terms of Service

Last updated: 2026-10-30

Effective date: 2026-10-30
Version: 1.0

If there is any inconsistency between the English and Japanese versions, the English version prevails.

1. Acceptance of these terms

Naruhodo Sensei ("the Service") is operated by ヤークス株式会社 (YARKS Inc., "we", "us"), 〒935-0011 富山県氷見市中央町9番47号. By creating an account or using the Service, you agree to these Terms of Service and to our Privacy Policy. If you do not agree, do not use the Service.

2. Eligibility and age

You must be 18 years of age or older to use the Service. You confirm your age when you first use the Service. The Service is not intended for anyone under 18.

The Service is offered in Japan and the United States. It is not offered to residents of the EU, EEA, UK, or Switzerland.

3. Your account

• You are responsible for keeping your sign-in credentials secure and for activity under your account.
• You agree to provide accurate information and to keep it up to date.
• You may sign in with email and password or with Google Sign-In.
• Notify us at support@yarks.jp if you believe your account has been compromised.

4. Licence to use the Service

We grant you a personal, non-exclusive, non-transferable, revocable licence to use the Service for your own language learning, subject to these terms. You may not resell, redistribute, or provide commercial access to the Service or its content without our written permission.

5. Subscriptions, credits, billing, and refunds

Payments are processed by our payment provider (Stripe). We never receive or store your card details.

a. Free access. Foundation and JLPT N5 learning content is available free of charge.

b. Subscription. A premium subscription unlocks content beyond Foundation and N5. The price is ¥1,100 per month, tax included. The subscription renews automatically each month until you cancel. There is no free trial.

c. Credits. Certain AI features (for example AI tutor chat and speaking practice) consume credits, which you can buy in packs:

Purchased credits do not expire. The number of credits a feature consumes is shown in the App.

d. Cancellation. You can cancel your subscription at any time. Cancellation stops future renewals; your subscription remains active until the end of the current paid period.

e. Refunds. Except where required by law, fees are non-refundable: once credits have been used, or once a subscription period is active, that amount is non-refundable. This does not limit any mandatory consumer rights you have under applicable law (see §12 and the Act on Specified Commercial Transactions disclosure on the Legal notice page).

f. Price changes. We may change prices or the features included; we will give notice of changes before they take effect, and changes will not affect a billing period you have already paid for.

g. App-store billing (future). If in the future you obtain the Service through the Apple App Store or Google Play, billing, renewals, and refunds for those purchases are handled by Apple or Google under their terms, and their rules prevail for those purchases.

6. Content you provide

You keep ownership of the text you type and the speech you provide to the Service. To operate the Service, you grant us a limited, worldwide, royalty-free licence to process that content solely to provide the features you use (for example, to generate an AI tutor reply or a speaking-practice transcript and corrections), as described in the Privacy Policy. We do not use your content to train AI models, and we do not publish it or share it with other users (the Service has no public or user-to-user sharing).

7. Acceptable use

You agree not to:

• use the Service for anything unlawful, or to harass, abuse, or harm others;
• attempt to access other users' data or our systems without authorization;
• interfere with, overload, or disrupt the Service;
• reverse engineer, scrape, or copy the Service or its content except as allowed by law;
• attempt to bypass the age check, region availability, paywall, or credit system;
• misuse the AI features to generate unlawful, harassing, or sexually explicit content.

8. Intellectual property

The Naruhodo Sensei name, the App, its design, and its learning content (lessons, explanations, questions, and other materials we create) are owned by ヤークス株式会社 (YARKS Inc.) or our licensors and are protected by intellectual-property laws. Some components are used under open-source or open-content licences (for example, certain kana stroke-order diagrams are used under a Creative Commons licence, with attribution). Nothing in these terms transfers ownership of our content to you.

9. AI-generated content — no guarantee of accuracy

Parts of the Service use AI to generate explanations, corrections, and conversation. AI output may be incorrect, incomplete, or inappropriate for your situation. The Service is a learning aid only. It is not a certified language qualification, not a substitute for professional instruction, and does not guarantee any exam result or level of proficiency. Use judgment and verify important information.

10. Availability and changes to the Service

We aim to keep the Service available but do not guarantee uninterrupted or error-free operation. We may add, change, suspend, or discontinue features, and may perform maintenance, at any time. We may impose reasonable limits on use to protect the Service.

11. Termination

You may stop using the Service and delete your account at any time (Profile → Data & privacy). We may suspend or terminate your access if you breach these terms, if required by law, or to protect the Service or other users. On termination, the licence in §4 ends. Sections that by their nature should survive (for example §6 licence to already-processed content, §8, §9, §12, §13) survive termination.

12. Disclaimers and limitation of liability

To the fullest extent permitted by law, the Service is provided "as is" and "as available", without warranties of any kind, except those that cannot be excluded by law.

Japan — consumers: Nothing in these terms excludes or limits our liability where doing so is prohibited by the Consumer Contract Act or other mandatory law. Under that Act, clauses that entirely exclude our liability to consumers, or that exclude liability for damage caused by our intent or gross negligence, are void and do not apply. Our liability for such cases remains as provided by law.

Subject to the above, and to the extent permitted by law, we are not liable for indirect, incidental, or consequential damages, or for loss arising from your reliance on AI-generated content, and our total liability for any claim relating to the Service is limited to the amount you paid us for the Service in the 12 months before the claim.

13. Governing law and disputes

These terms are governed by the laws of Japan. The Toyama District Court shall have exclusive jurisdiction as the court of first instance for any dispute, to the extent permitted by law and without depriving a consumer of any mandatory protection or venue available under applicable consumer law.

14. Changes to these terms

We may update these terms. If we make a material change, we will update the effective date and, where appropriate, notify you in the App. Your continued use after a change means you accept the updated terms.

15. Contact

Questions about these terms: support@yarks.jp.