Terms of Service

These Terms of Service ("Terms") are a binding agreement between you and Estate One Company Limited ("we", "us", "our") governing your use of Nihongo and related services (the "Service"). By creating an account or using the Service, you accept these Terms and our Privacy Policy. If you do not agree, do not use the Service.

1Eligibility & accounts

• You must be at least 13 years old (or the age of digital consent where you live) and able to form a binding contract. If you are a minor, you may use the Service only with the consent of a parent/guardian who agrees to these Terms.
• You are responsible for your account credentials and all activity under your account. Keep your login secure and notify us of any unauthorized use.
• Provide accurate information and keep it current.

2License to use the Service

We grant you a limited, personal, non-exclusive, non-transferable, revocable license to use the Service for your personal, non-commercial learning. You may not copy, modify, reverse-engineer, scrape, resell, or create derivative works from the Service or its content except as the law expressly permits or as allowed for specific open-licensed data (see Data sources & licenses).

3Subscriptions, payments & renewals

• The Service offers a free tier and paid tiers (e.g., Pro, Ultra). Paid features and limits are described at purchase.
• Subscriptions are billed through the Apple App Store, Google Play, or our payment processor and are subject to their terms. Auto-renewal: subscriptions renew automatically for the same period at the then-current price unless you cancel at least 24 hours before the period ends.
• Manage or cancel in your Apple/Google account settings. Deleting the app does not cancel a subscription.
• Prices may change; we will give notice as required, and changes apply to the next billing period.
• Refunds are governed by the applicable store's policy and our Subscriptions & Refunds policy. Except where required by law, payments are non-refundable.

4Acceptable use

You agree not to:

• break the law or infringe others' rights;
• upload, submit, or share content that is illegal, infringing, hateful, harassing, threatening, sexually explicit, exploitative of minors, defamatory, deceptive, spam, or that contains malware or others' private information;
• misuse AI features to generate prohibited content or to harass/deceive others;
• attempt to access accounts/data you're not authorized to, probe or disrupt the Service, circumvent limits or security, or use bots/automated scraping;
• use the Service to build a competing product or to train machine-learning models.

See our Community Guidelines for content rules. We may remove content and suspend or terminate accounts that violate them.

5Your content & the license you give us ("UGC")

• You keep ownership of the sentences, readings, notes, photos, and other content you create or submit ("Your Content").
• By submitting Your Content to public areas (e.g., the community library or shared readings), you grant us and other users a worldwide, non-exclusive, royalty-free, sublicensable license to host, store, reproduce, display, distribute, and create AI analyses/derivatives of it for operating, promoting, and improving the Service. This license ends when you delete the content, except for copies others have saved, backups, or anonymized/aggregated data.
• You represent and warrant that you own or have the rights to Your Content and that it does not infringe any third party's rights or violate any law. Do not submit copyrighted text (e.g., from books, manga, lyrics, or paywalled sources) or photograph others' copyrighted material and share it unless you have the right to do so.
• We are not obligated to monitor content but may review, remove, or restrict any content at our discretion. We are a neutral host of user content and are not responsible for it (see Sections 12–13).

6AI-generated content

The Service uses third-party artificial intelligence to generate example sentences, readings, translations, grammar explanations, conversation, and image/text analysis. AI output may be inaccurate, incomplete, outdated, or inappropriate. It is provided for educational and entertainment purposes only and is not professional, certified, legal, medical, financial, immigration, or other expert advice. Do not rely on AI output for any important decision without independent verification. See Disclaimers.

7Educational disclaimer

Nihongo is a study aid. We do not guarantee any learning outcome, fluency level, test/JLPT result, or that content is free of error. Language data is compiled from curated and open sources and may contain mistakes.

8Intellectual property

The Service, including its software, design, and our trademarks and logos, is owned by us or our licensors and protected by law. Certain language data is provided under open licenses and remains subject to those licenses (see Data sources & licenses). Except for the limited license in Section 2, we grant you no rights in our intellectual property.

9Third-party services

The Service integrates third-party services (e.g., Anthropic, Supabase, Google, Apple). Your use of them may be subject to their terms, and we are not responsible for them. Links to third-party sites are provided for convenience only.

10Copyright (DMCA)

We respect intellectual property and respond to valid takedown notices. See our Copyright / DMCA Policy. We may terminate repeat infringers.

11Termination

You may stop using the Service and delete your account at any time. We may suspend or terminate your access at any time, with or without notice, if you violate these Terms, create legal/security risk, or if we discontinue the Service. Sections that by their nature should survive (e.g., 5–8, 12–16) survive termination.

12Disclaimers (warranties)

THE SERVICE AND ALL CONTENT (INCLUDING AI OUTPUT AND USER CONTENT) ARE PROVIDED "AS IS" AND "AS AVAILABLE" WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, AND NON-INFRINGEMENT. WE DO NOT WARRANT THAT THE SERVICE WILL BE UNINTERRUPTED, SECURE, OR ERROR-FREE, OR THAT CONTENT IS ACCURATE OR RELIABLE. SOME JURISDICTIONS DO NOT ALLOW CERTAIN DISCLAIMERS, SO SOME MAY NOT APPLY TO YOU.

13Limitation of liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, ESTATE ONE COMPANY LIMITED AND ITS OWNERS, EMPLOYEES, AND SUPPLIERS WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, EXEMPLARY, OR PUNITIVE DAMAGES, OR FOR LOST PROFITS, DATA, OR GOODWILL, ARISING FROM OR RELATED TO THE SERVICE OR THESE TERMS. OUR TOTAL LIABILITY FOR ALL CLAIMS WILL NOT EXCEED THE GREATER OF (a) THE AMOUNT YOU PAID US IN THE 12 MONTHS BEFORE THE CLAIM, OR (b) US$50. THESE LIMITS APPLY EVEN IF A REMEDY FAILS OF ITS ESSENTIAL PURPOSE. NOTHING LIMITS LIABILITY THAT CANNOT BE LIMITED BY LAW (e.g., gross negligence, fraud, or certain consumer rights).

14Indemnification

You agree to indemnify and hold harmless Estate One Company Limited from any claims, damages, losses, and expenses (including reasonable legal fees) arising from (a) Your Content, (b) your use of the Service, (c) your violation of these Terms or the law, or (d) your infringement of any third party's rights.

15Disputes; governing law

• These Terms are governed by the laws of Japan, without regard to conflict-of-laws rules.
• [Optional — confirm with your attorney] Any dispute may be resolved by binding individual arbitration administered by [Arbitration body] in [Arbitration venue], with a waiver of class actions. You may opt out within 30 days by emailing support@bynetica.com. (In Japan a consumer may generally rescind a pre-dispute arbitration agreement; such clauses are also restricted or unenforceable for EU/UK consumers. Your attorney should confirm whether to keep this clause at all for a Japan-based consumer service.)
• Where arbitration does not apply, the Nara District Court (or the district court for our registered office) has exclusive jurisdiction as the court of first instance. Mandatory consumer protections under Japan's Consumer Contract Act (消費者契約法しょうひしゃけいやくほう) and your local law still apply.

16App-store terms

If you download the App from the Apple App Store: these Terms are between you and us, not Apple; Apple is not responsible for the App or any claims relating to it; Apple and its subsidiaries are third-party beneficiaries of these Terms and may enforce them; and you confirm you are not in a U.S.-embargoed country or on a prohibited-parties list. If from Google Play, Google's terms also apply.

17General

These Terms (with the Privacy Policy, Community Guidelines, DMCA Policy, and Disclaimers) are the entire agreement. If a provision is unenforceable, the rest remains in effect. Our failure to enforce a right is not a waiver. You may not assign these Terms; we may. We may update these Terms and will post the new version with a new date; material changes will be notified, and continued use means acceptance.

18Contact

Estate One Company Limited — 奈良市月ヶ瀬桃香野3534-1 — support@bynetica.com