About Tsumilith

• Company: Ichinichi Inc.
• Service: Tsumilith
• Address: 2-14-13 Nishi-Gotanda, Shinagawa-ku, Tokyo, Japan
• Business: planning, development and operation of a language learning platform
• Contact: the contact form in the app

Last updated: September 13, 2026

These Terms of Service (the "Terms") set out the conditions for using "Tsumilith" (the "Service"), a language learning service provided by Ichinichi Inc. ("we", "us" or "our"). Everyone who uses the Service ("you" or "Users") must agree to these Terms and our Privacy Policy before using the Service.

This English version is a translation provided for convenience. If there is any inconsistency, the Japanese version prevails (see Article 22).

Scope

• These Terms apply to all relationships between you and us regarding your use of the Service.
• Notices, price lists, help pages and similar rules we publish in the Service ("Supplementary Rules") form part of these Terms. If a Supplementary Rule conflicts with these Terms, the Supplementary Rule prevails.
• Nothing in these Terms affects any rights you have under the mandatory laws of the country or region where you live that cannot be excluded or limited by contract ("Mandatory Rights").

Definitions

• "Service": the web application named "Tsumilith" and related services that help people learn English, Japanese and other languages
• "Account": the information you register in order to use the Service
• "User Content": words, phrases, diary entries, notes, lyrics, audio, images and other information you enter, register or send to the Service
• "AI Output": translations, grading, explanations, example sentences, summaries, replies and other content generated by the Service's AI features
• "Tokens": usage credits that we grant or sell for use of AI features and other functions, usable only within the Service
• "Consumer": an individual who uses the Service other than for business purposes

Eligibility and Age

• You must be at least 13 years old to use the Service. Children under 13 may not use the Service.
• If you are below the age at which the law of your country or region requires parental consent for processing personal data (for example, under 16 in some countries of the European Economic Area), or if you are a minor, you may use the Service only with the consent of your parent or guardian.
• You may use the Service from outside Japan. However, you may not use the Service if you live in a country or region to which providing the Service is prohibited under the export control or sanctions laws of Japan, the United States or other applicable jurisdictions, or if you are a sanctioned person.

Accounts

• You register an Account by the method we specify (including signing in with a Google account or similar).
• You must keep your registration information accurate and up to date, and you are responsible for keeping your login credentials secure. You may not transfer, lend or share your credentials with anyone.
• Each person may hold only one Account unless we permit otherwise.

The Service

• The Service provides learning features such as saving and training words and phrases, tests, a diary, notes, lyrics, news, conversation practice and an AI coach.
• The Service is currently provided as a beta. Features, specifications and token consumption may change as we improve the Service.

Fees and Tokens

• The Service is currently provided free of charge. We do not currently ask you to pay any fees.
• We may grant free Tokens from time to time. Free Tokens have a validity period and expire when that period ends or when they are periodically reset.
• If we start selling Tokens or offering other paid features ("Paid Services") in the future, we will show the price, payment method, delivery timing, refund conditions and other terms on the purchase screen and in our "Commercial Disclosure". You purchase Paid Services by agreeing to the terms shown at the time of purchase.
• Prices for Paid Services are shown in Japanese yen, including Japanese consumption tax, and payments are processed by our payment provider, Stripe, Inc. Any currency conversion or foreign transaction fees charged by your card issuer are your responsibility. If value-added tax or similar taxes apply in your country, they will be shown on the purchase screen.
• Purchased Tokens can be used only within the Service and cannot be exchanged for cash, refunded or transferred to other Users, except through features we expressly provide.
• If we change the prices of Paid Services, token consumption or other conditions, we will notify you in the Service before the change takes effect. Changes apply to purchases and use made after the change.

Refunds and Right of Withdrawal

• Purchased Tokens are digital content delivered immediately after purchase. Except as required by law, we do not offer refunds after purchase.
• If you are a Consumer in the European Economic Area, the United Kingdom or any other country or region whose laws give you a right to withdraw from the contract (for example, within 14 days of purchase), you have that right in accordance with those laws. However, if at the time of purchase you expressly request that we deliver the Tokens during the withdrawal period and acknowledge that you will lose your right of withdrawal as a result, you lose that right as provided by law.
• If Tokens are not delivered, or you are unable to use the Service, for reasons attributable to us, we will re-grant the Tokens or provide a refund to a reasonable extent.

User Content

• You (or the relevant rights holders) retain all rights in your User Content.
• You grant us a free license to copy, store, process and display your User Content, and to send it to third-party AI services for AI features, to the extent necessary to provide, maintain and improve the Service and to handle problems. This license ends when the retention period set out in our Privacy Policy expires after you delete your Account.
• You represent that you have the necessary rights to your User Content and that it does not infringe anyone's rights. If you register lyrics, news articles or other copyrighted works, you do so for your own private study and at your own responsibility.
• Your diary entries, notes and similar content are visible only to you and are never made public to other Users.

AI Features

• The Service's AI features use AI models provided by third parties such as Google LLC. When you use an AI feature, what you enter is sent to that third party to generate the AI Output.
• AI Output is generated automatically and may contain errors, inaccurate information or unnatural expressions. We do not guarantee that AI Output is accurate, complete or useful. Please check important information with dictionaries, textbooks or experts.
• You may freely use AI Output for your own learning. You may not use AI Output to build a service that substitutes for the Service, or redistribute or sell it in bulk.
• Please do not enter sensitive information (such as health, religion or political beliefs), other people's personal information or confidential information into AI features.

Prohibited Conduct

You must not:

• violate any law, public order or morals, or these Terms;
• infringe the intellectual property, privacy, reputation or other rights of us, other Users or third parties;
• interfere with the operation of the Service or place an excessive load on our servers or AI features;
• attempt unauthorized access, exploit vulnerabilities, reverse engineer or otherwise analyze the Service;
• use bots, scripts or other automated means, or circumvent usage limits or pricing;
• create multiple Accounts improperly, or buy, sell or transfer Accounts or Tokens;
• resell, republish or distribute AI Output or content of the Service in bulk for commercial purposes without our permission;
• provide benefits to or otherwise cooperate with organized crime groups or other anti-social forces; or
• engage in any other conduct similar to the above.

Intellectual Property

All intellectual property rights in the software, design, logos, text and other elements of the Service (excluding User Content) belong to us or our licensors. We grant you a non-transferable, non-exclusive right to use the Service for personal purposes in accordance with these Terms.

Changes, Suspension and Termination of the Service

• We may add, change or remove features. We will give reasonable advance notice of changes that would significantly disadvantage you.
• We may temporarily suspend all or part of the Service for maintenance, failures, natural disasters or other unavoidable reasons.
• We may end all or part of the Service by giving at least 30 days' notice. If you hold valid purchased Tokens when the Service ends, we will refund the unused portion or take other appropriate measures in accordance with applicable law.

Suspension of Accounts and Termination

• If you violate these Terms, provide false registration information, or we otherwise reasonably determine that it is inappropriate for you to continue using the Service, we may suspend or delete your Account with prior notice (or with notice afterwards in urgent cases).
• You may delete your Account at any time from the Settings screen, which ends your agreement under these Terms.
• When you delete your Account, your Account, learning data, User Content and other data linked to you are deleted and cannot be restored. Any Tokens you hold (including purchased Tokens) also expire. However, payment records that we are required by law to keep are retained, in a form that does not directly identify you, for the period set out in our Privacy Policy.
• To prevent abuse such as repeatedly obtaining free Tokens, the same email address as a deleted Account cannot be used to register an Account for three months after deletion.

Disclaimer of Warranties

We do not guarantee that the Service will be uninterrupted or error-free, that it will fit your particular purpose, or that you will achieve any particular learning results. This does not affect your Mandatory Rights, including any statutory guarantees for Consumers.

Limitation of Liability

• Except in cases of our willful misconduct or gross negligence, our liability for any damage you suffer in connection with the Service is limited to the total fees you paid us in the six months before the month in which the damage occurred.
• The preceding paragraph does not apply to damage caused by our willful misconduct or gross negligence, to death or personal injury, or where the law does not allow liability to be limited.
• If you are a Consumer, this Article does not apply to the extent it is invalid under the Consumer Contract Act of Japan or the consumer protection laws of the country or region where you live.

Notices and Contact

• We give notices to you through announcements in the Service, emails to your registered address or other methods we consider appropriate.
• You can contact us through the contact form in the Service. We accept inquiries in English.

Changes to These Terms

• We may change these Terms when laws change, the Service changes or there is another reasonable need.
• For changes that are unfavorable to you, we will notify you in the Service of the changes and their effective date at least 14 days before they take effect. To keep using the Service after the change, you must agree to the updated Terms.
• If you do not agree to a change, you may delete your Account and stop using the Service.

Assignment

You may not assign your position or rights and obligations under these Terms to anyone without our prior consent. We may transfer our contractual position regarding the Service to a successor in connection with a business transfer or similar transaction, and you agree to this in advance. We will notify you beforehand in that case.

Exclusion of Anti-Social Forces

You represent and warrant that you are not, and have no relationship with, any organized crime group or other anti-social force.

Severability

If any provision of these Terms is held invalid or unenforceable under applicable law, the remaining provisions continue in full force.

Governing Law and Jurisdiction

• These Terms are governed by the laws of Japan.
• The Tokyo District Court has exclusive jurisdiction as the court of first instance over disputes regarding the Service.
• However, if you are a Consumer, this does not deprive you of the protection of the mandatory laws of the country or region where you live, or of your right to bring proceedings before the courts of your place of residence. Consumers in the European Union may also use out-of-court dispute resolution procedures available to them.

Language

These Terms are written in Japanese. Translations into English or other languages are provided for reference only, and if there is any inconsistency, the Japanese version prevails, unless the law of your place of residence requires the translated version to prevail.

Company Information and Contact

• Company: Ichinichi Inc.
• Address: 2-14-13 Nishi-Gotanda, Shinagawa-ku, Tokyo, Japan
• Contact: the contact form in the Service

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Revision history

• April 29, 2026: First edition
• September 13, 2026: Full revision for users living outside Japan, including the European Economic Area and the United Kingdom (added or changed provisions on age, Tokens, refunds and withdrawal, AI Output, data deletion and re-registration after account deletion, limitation of liability, governing law and jurisdiction, and language)

Last updated: September 13, 2026

Ichinichi Inc. ("we", "us" or "our") handles the personal information (including personal data; the same applies below) of users ("you" or "Users") of our language learning service "Tsumilith" (the "Service") in accordance with the Act on the Protection of Personal Information of Japan (the "APPI"), the EU General Data Protection Regulation (the "GDPR"), the UK GDPR and other laws that apply to you.

This English version is a translation provided for convenience. If there is any inconsistency, the Japanese version prevails (see Section 13).

1. Controller and Contact

• Company (data controller): Ichinichi Inc.
• Address: 2-14-13 Nishi-Gotanda, Shinagawa-ku, Tokyo, Japan
• Contact: the contact form in the Service, or email 【要記入：問い合わせ用メールアドレス】 (available even if you do not have an account or cannot sign in; we respond in English)

2. Information We Collect

Account and profile

• Your email address and identifiers from sign-in providers (if you sign in with Google or similar)
• Nickname, profile image, date of birth, gender, country or region, hobbies, occupation and bio (all optional)
• Settings such as your native language, learning language, level, goals and coach style

Learning data and User Content

• Words, phrases and meanings you save, decks, answers and results of training and tests, and mastery levels
• Diary entries, notes, memos, lyrics, news reading history, and conversation and chat content
• Recognized text when you use voice input (the audio itself is processed by your browser's speech recognition, and we do not store it)

Inquiries and bug reports

• The content of your inquiries and our correspondence
• When you send a bug report: a screenshot, information about the page structure, recent operation and network logs, device and browser information, and your approximate country, region and city (estimated from your IP address)

Usage and device information

• IP address, browser and OS type, screen size, time zone and language settings
• Pages viewed and actions taken, feature usage counts and error records
• Identifiers from cookies and similar technologies (see Section 8)

Payment information (if we start offering paid features)

• Purchase history, payment status and transaction identifiers. Card numbers and other payment details are collected by our payment provider, Stripe, Inc., and we do not hold them.

We do not intentionally collect special categories of personal data (sensitive personal information). Please do not include such information in your diary or in what you enter into AI features.

3. Purposes and Legal Bases

We use your information for the following purposes. For Users in the European Economic Area (EEA) and the United Kingdom, the legal basis for each purpose is shown in parentheses.

• Providing the Service, including account management, storing learning data, AI translation, grading, explanations, example sentences and text-to-speech (performance of a contract)
• Personalizing your learning, such as questions and examples matched to your level and interests (performance of a contract)
• Responding to inquiries and bug reports and investigating problems (performance of a contract; legitimate interests)
• Preventing abuse, keeping the Service secure and enforcing usage limits, including restricting re-registration for a period after Account deletion (legitimate interests)
• Improving the Service and developing new features, using statistics that do not identify you (legitimate interests)
• Analyzing usage with Google Analytics 4 (consent; see Section 8)
• Sending important notices, including changes to our terms (performance of a contract; legal obligation)
• Processing payments for paid features and keeping accounting and tax records (performance of a contract; legal obligation)
• Complying with the law (legal obligation)

You may object to processing based on our legitimate interests (see Section 7).
We do not make decisions based solely on automated processing that produce legal effects concerning you or similarly significantly affect you (Article 22 GDPR). AI grading and similar features are provided only to support your learning.

4. Service Providers

We entrust the handling of personal information to, or use as external services, the following providers to the extent necessary to provide the Service. We have entered into contracts (such as data processing agreements) requiring appropriate handling of personal information, or have agreed to their terms and data protection conditions.

• Clerk, Inc. (United States): user authentication and account management
• Supabase, Inc. (data stored in Japan, Tokyo region): database
• Vercel Inc. (United States and edge locations worldwide): hosting of the web application
• Google LLC (United States): AI features through the Gemini API, text-to-speech through Cloud Text-to-Speech, video search through the YouTube Data API, and usage analysis through Google Analytics 4
• Resend, Inc. (United States): sending reply emails to inquiries
• Stripe, Inc. (United States): payment processing (if we start offering paid features)

When you use AI features, what you enter and the learning data needed to generate the output (such as saved words and your level) are sent to Google LLC. Under its paid API terms, Google states that it does not use this content to train its AI models.

The Service uses YouTube API Services. Your use of YouTube is subject to the YouTube Terms of Service (https://www.youtube.com/t/terms), and Google's handling of information is subject to the Google Privacy Policy (https://policies.google.com/privacy).

5. International Transfers

• As described in Section 4, we entrust personal information to providers located in the United States. The United States does not have a comprehensive federal privacy law equivalent to the APPI; personal information is protected by state laws (such as the California Consumer Privacy Act) and sector-specific laws. Information about other countries' systems is available on the website of Japan's Personal Information Protection Commission (https://www.ppc.go.jp/en/).
• Through our contracts with these providers, we ensure systems that meet the standards of the APPI (security measures, prohibition of use for other purposes, oversight of subcontracting and so on). We will provide information about these measures upon request.
• Personal data of Users in the EEA and the United Kingdom is transferred to us in Japan, which the European Commission and the UK government have recognized as providing an adequate level of protection. Onward transfers from us to providers in the United States are made on the basis of appropriate safeguards, such as the provider's participation in the EU-U.S. Data Privacy Framework (including the UK Extension) or the European Commission's Standard Contractual Clauses (including the UK Addendum).

6. Disclosure to Third Parties

We do not provide your personal information to third parties except:

• with your consent;
• where required by law;
• where necessary to protect a person's life, body or property and it is difficult to obtain your consent; or
• when our business is succeeded through a business transfer, merger or similar transaction (the successor will protect your information at a level equivalent to this Policy).

We do not sell your personal information or share it with third parties for targeted advertising.

7. Your Rights

You may ask us to:

• notify you of the purposes of use of, or disclose, the personal data we hold about you (including records of provision to third parties);
• correct, add to or delete that data; and
• stop using, erase or stop providing that data to third parties.

If you are in the EEA or the United Kingdom, you also have the following rights under the GDPR:

• the rights of access, rectification, erasure ("right to be forgotten") and restriction of processing;
• the right to data portability (receiving your data in a machine-readable format);
• the right to object to processing based on legitimate interests;
• the right to withdraw consent at any time (without affecting the lawfulness of processing before withdrawal); and
• the right to lodge a complaint with a supervisory authority, for example in the country where you live or work.

You can view and change much of your information in Settings, and you can delete your Account there. You can withdraw your consent to analytics at any time in Settings. For other requests, please contact us using the details in Section 1. After verifying your identity, we will respond in principle within one month (or within any period required by law). Requests are free of charge in principle.

Residents of certain U.S. states may have rights under state law to access, delete or correct their personal information. We will not discriminate against you for exercising these rights.

8. Cookies and Similar Technologies

The Service uses cookies, local storage and similar technologies for the following purposes:

• Essential: keeping you signed in, security, and recording your consent choices (no consent required)
• Functional: display settings, text-to-speech settings and saving unfinished input (no consent required)
• Analytics: measuring usage with Google Analytics 4 (access time, pages viewed, features used, device information and so on)

Consent to analytics is optional and can be chosen on the consent screen when you first use the Service. You can use the Service without consenting. For access from the EEA, the United Kingdom and Switzerland, we do not use analytics cookies until you consent. You can change your choice at any time in Settings. For how Google handles information, see the Google Privacy Policy (https://policies.google.com/privacy) and "How Google uses information from sites or apps that use our services" (https://policies.google.com/technologies/partner-sites).

9. Retention

• Account information, learning data, User Content and consent records: while your Account is active. We delete them when you delete your Account, and they are erased from backups within 90 days at most
• Inquiries and bug reports: two years after the matter is closed. Screenshots and page structure information attached to bug reports are deleted 90 days after they are sent
• Operation, network and error logs: one year after collection
• Payment and accounting records: for the period required by law (seven years under Japanese corporate tax law). After Account deletion, we keep them with your user ID replaced by a pseudonym that cannot be traced back
• Information for the re-registration restriction: for three months after Account deletion, we keep a value derived from the deleted Account's email address (not the address itself, but an irreversible transformation of it), used only to check whether the same address is being used to register again
• Statistics that do not identify you: may be kept without a fixed period

When you delete your Account, all information linked to you is deleted, except what must be kept for legal reasons or to prevent abuse (payment records and the information for the re-registration restriction). Information past its retention period is deleted by a daily automated process.

10. Security

We take measures to prevent leakage, loss or damage of personal information, including encryption in transit, access control to our database, limiting administrative privileges and supervising our service providers. If a personal data breach occurs that must be reported or notified under applicable law, we will report it to the supervisory authority and notify you.

11. Age

The Service is intended for people aged 13 and over. We do not knowingly collect personal information from children under 13. If we learn that we have collected such information, we will delete it promptly. If you are below the age at which the law of your place of residence requires parental consent, please use the Service only with the consent of your parent or guardian.

12. Changes to This Policy

We may change this Policy in response to changes in law or in the Service. For significant changes, we will notify you in the Service at least 14 days before they take effect and ask for your consent again where required.

13. Language

This Policy is written in Japanese. The English version is a translation provided for reference, and if there is any inconsistency, the Japanese version prevails, unless the law of your place of residence provides otherwise.

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Revision history

• April 29, 2026: First edition
• June 3, 2026: Added analytics with Google Analytics 4 and how consent is obtained
• September 13, 2026: Full revision for users living outside Japan, including the EEA and the United Kingdom (added legal bases, updated service providers to reflect actual use, international transfers, GDPR rights, optional consent to cookies, retention periods and deletion on account deletion, and age)

Last updated: September 13, 2026

This is our disclosure based on the Act on Specified Commercial Transactions of Japan. The English version is a translation provided for convenience; the Japanese version prevails.

The Service is currently provided free of charge, and we do not sell anything at this time. When we start offering paid features (sales of Tokens), the following will apply.

Seller

Ichinichi Inc.

Person responsible for operations

We will disclose this without delay upon request.

Address

2-14-13 Nishi-Gotanda, Shinagawa-ku, Tokyo, Japan

Phone number

We will disclose this without delay upon request. Please contact us at the email address below or through the contact form in the Service.

Email address

【要記入：問い合わせ用メールアドレス】

Price

The price shown on the purchase screen (in Japanese yen, including Japanese consumption tax)

Additional fees

• Internet connection charges
• Currency conversion or foreign transaction fees charged by your card issuer if you use a card issued outside Japan
• Any value-added tax or similar taxes that apply in your country will be shown on the purchase screen

Payment methods

Credit cards and other payment methods offered by our payment provider, Stripe, Inc.

Payment timing

Payment is made when you complete the purchase

Delivery

Tokens are added to your account in the Service immediately after payment is completed

Returns and cancellations

• Due to the nature of digital content, we do not accept returns or offer refunds after purchase. However, if Tokens are not delivered for reasons attributable to us, we will re-grant them or issue a refund.
• If you are a consumer in the European Economic Area, the United Kingdom or any other place whose laws give you a right of withdrawal, those laws apply. If at the time of purchase you agree to receive the Tokens during the withdrawal period and acknowledge that you will lose your right of withdrawal, you lose that right.
• For details, see Articles 6 and 7 of the Terms of Service.

System requirements

The latest versions of Google Chrome, Microsoft Edge and Safari (voice input and text-to-speech depend on your device and browser)