Oto Oi

OtoOi Terms of Use

Last updated: October 25, 2026 Established: June 2, 2026

These Terms of Use (the "Terms") set out the conditions for using "OtoOi" (the "Service"), a language learning service provided by Yutaka Imai (trade name: OtoOi; "we" or "us"). By using the Service, you agree to these Terms.

This is an English translation of the Japanese Terms of Use. The Japanese version is the official text (Article 14).

Article 1 (Scope)

These Terms apply to all relationships between us and users regarding the use of the Service.

Article 2 (Definitions)

  1. "Service" means the language learning service "OtoOi" provided by us (including the app and web versions of the Korean reading app "OtoOi Reader" and the website otooi.com) and any related services.
  2. "Content" means audio, text, images, learning materials and any other information provided on the Service.
  3. "Data" means article data, explanations of sentence structure, words and grammar, indexes and other information provided on the Service (including information that does not qualify as Content).
  4. "Subscription" means an automatically renewing subscription that makes certain features of the Service available for a fee.
  5. "User" or "you" means a person who agrees to these Terms and uses the Service.

Article 3 (User identifier)

  1. The Service does not require you to register an account with an email address or similar.
  2. The app version of the Service assigns a user identifier to each device, for purposes such as checking whether you have a Subscription (Privacy Policy, Section 2.1).
  3. If your user identifier changes because you delete the app, change devices or similar, you can carry over your Subscription with "Restore Purchases" in the app. You are responsible for managing the app store account (such as your Apple ID) used for your Subscription.

Article 4 (Fees and Subscriptions)

  1. The basic features of the Service are free of charge. Some features are available with a Subscription. The features included in the Subscription, its fees and its periods are shown in the Service (on the subscription screen) and in the Legal notice under the Act on Specified Commercial Transactions (in Japanese).
  2. Subscriptions are purchased and paid for by the methods set by the operator of the app store (such as the App Store). We do not obtain payment information such as credit card numbers.
  3. A Subscription renews automatically on the same terms unless you cancel it at least 24 hours before the end of the current period. You can cancel it in your app store account settings. If you cancel, you can keep using the Subscription features until the end of the current period.
  4. If a free trial is offered, you will be charged the Subscription fee when the trial ends unless you cancel at least 24 hours before it ends.
  5. Refunds after purchase follow the procedures set by the operator of the app store. Except as required by law, we do not refund Subscription fees.
  6. We may change the fees or contents of Subscriptions. If we change the fees, we will notify you in advance in accordance with the procedures set by the operator of the app store.

Article 5 (Learning records and the nature of the Service)

  1. The Service stores your learning records (pieces you have read, marks such as "Read" and "Known", display settings, etc.) on your device and does not store them on our servers.
  2. Learning records on your device may be erased if you delete the app, change or clear your device or browser settings or data, or if your device breaks down or is replaced. We cannot restore them.
  3. Because we are continuously improving the Service, bugs, changes in specifications or interruptions may occur. We are not liable for any damage caused to you by these, except as provided in Article 9.

Article 6 (Intellectual property)

  1. All intellectual property rights relating to the Service and the Content, including copyrights, patents and trademarks, belong to us or to their legitimate rights holders.
  2. Through the Service, you are granted only a non-exclusive right to use the Content and Data for private, non-commercial learning purposes. No intellectual property rights are transferred to you.

Article 7 (Prohibited conduct)

When using the Service, you must not:

  1. Act in violation of laws, regulations, or public order and morals
  2. Copy, modify, republish, redistribute, sell, transmit to the public or otherwise use the Content or Data beyond the scope we permit
  3. Reverse engineer, decompile or otherwise analyze the Service
  4. Obtain or collect the Content or Data of the Service with crawlers, scraping tools, bots or other automated means (except normal collection by search engines and other collection we permit)
  5. Use the Content or Data of the Service to train or develop machine learning or artificial intelligence, or to create datasets
  6. Circumvent or disable access restrictions of the Service, restrictions on the scope of use based on Subscriptions, or other technical protection measures
  7. Infringe our or any third party's intellectual property rights or other rights or interests
  8. Interfere with the operation of the Service, or place an excessive load on servers or networks
  9. Gain unauthorized access to the Service or use it by other improper means
  10. Engage in any other conduct that we reasonably consider inappropriate

Article 8 (Restriction of use)

If you violate these Terms, or if we otherwise consider it necessary, we may restrict all or part of your use of the Service without prior notice.

Article 9 (Disclaimer of warranties and limitation of liability)

  1. We do not warrant that the Service will suit your particular purpose, that you will achieve the learning results you expect, that the content of the Service (including translations, explanations and notes) is accurate, or that the Service is free from defects.
  2. If we cause damage to you in connection with the Service intentionally or through gross negligence, we will compensate you for that damage.
  3. If our slight negligence (meaning negligence other than intent or gross negligence) results in non-performance of our obligations or a tort that causes damage to you, we will compensate you only for the ordinary damage you actually incurred, up to the higher of (a) the total Subscription fees you paid for the Service during the 12 months before the date on which the cause of the damage occurred, or (b) 5,000 yen. This paragraph applies only to cases of our slight negligence.

Article 10 (Changes to and termination of the Service)

We may change the content of the Service or stop providing it after giving you prior notice (except in emergencies). If we stop providing Subscriptions, we will announce it in the Service with reasonable advance notice and stop automatic renewals.

Article 11 (Changes to these Terms)

We may change these Terms when we consider it necessary, in accordance with Article 548-4 of the Civil Code of Japan. When we do, we will announce the changed content and its effective date in the Service or by other means before the effective date. If you use the Service on or after the effective date, you are deemed to have agreed to the changed Terms.

Article 12 (Handling of personal information)

Your information in the Service is handled in accordance with our separate Privacy Policy.

Article 13 (Governing law and jurisdiction)

  1. These Terms are governed by the laws of Japan.
  2. Any dispute relating to the Service or these Terms shall be subject to the exclusive jurisdiction of the court having jurisdiction over our address as the court of first instance.
  3. Nothing in these Terms limits any rights you have under the laws of the country or region where you live that cannot be excluded or limited by contract (including rights relating to consumer protection).

Article 14 (Language)

The Japanese text of these Terms is the official version. If there is any discrepancy between a translation of these Terms (including this English version) and the Japanese version, the Japanese version prevails.