Terms of Service

Last updated: August 21, 2025

1. Agreement to Terms

These Terms of Service ("Terms") define the conditions for using our service (including this website, and hereinafter, no particular distinction is made between the two). These Terms apply to all users who use our service.

By using our service, users are deemed to have given valid and irrevocable consent to these Terms. Users who do not agree to these Terms may not use our service.

2. Service Description

Butango is a language learning mobile application that provides:

• Interactive AI-powered conversation practice
• Vocabulary building with Oxford word lists
• Progress tracking and analytics
• Voice recognition and text-to-speech features
• Cross-device synchronization of learning data
• Premium content and features through subscription

3. User Registration

Those wishing to use our service must agree to these Terms and apply for user registration through methods designated by our company. User registration is completed when our company approves the application.

4. Registration Rejection

Our company may refuse registration applications if we determine any of the following reasons exist. We bear no obligation to disclose reasons for registration rejection:

• When false information is provided
• When the application is from someone who has previously violated these Terms
• When our company otherwise deems registration inappropriate

5. Use by Minors

If users are minors, they must obtain consent from their legal guardians before using our service. Smartphones and other devices necessary for using our service must also be used with the consent of legal guardians.

If a user who began using our service without legal guardian consent reaches the age of majority, they are deemed to have ratified their usage during their minority.

6. Login Information Management

Users must appropriately manage their service login information at their own responsibility. Users may not transfer, lend, or share login information with third parties under any circumstances. Our company bears no responsibility for damages caused by third-party use of login information, except when our company has intentional or gross negligence.

7. Content Usage

Our company grants users non-transferable, non-sublicensable, non-exclusive usage rights for private use within the scope of service usage for text, images, videos, audio, music, software, programs, code, and other content provided by our service. For paid content, private usage rights within service scope are granted upon completion of payment of usage fees designated by our company. Any use of service content beyond this scope is strictly prohibited.

Users acknowledge in advance that if they lose the right to use our service for any reason, they will no longer be able to use any service content.

8. Late Payment Charges

Users who are late in paying monetary obligations to our company must pay late payment charges to our company at a rate of 14.6% per year.

9. Advertisement Display

Our company may display advertisements from our company or third parties in our service.

10. Prohibited Activities

Users must not engage in the following activities when using our service:

• Acts violating laws, court judgments, decisions, orders, or legally binding administrative measures, or acts that encourage such violations
• Acts related to criminal activities
• Acts infringing on intellectual property rights of our company or third parties
• Acts infringing on portrait rights, privacy, honor, or other rights or interests of our company or third parties
• Acts placing excessive burden on our company's or third parties' servers or networks, or interfering with their normal operation
• Acts that may interfere with our service operations
• Unauthorized access attempts
• Acts analyzing service source code through reverse assembly, reverse compilation, reverse engineering, etc.
• Unauthorized access to systems connected to our service or unauthorized alteration or deletion of information stored in our company equipment
• Acts of copying, transmitting, transferring, lending, or modifying our service websites or software
• Acts of paid lending, transfer, or trading of service accounts or content to third parties
• Commercial use of information obtained through our service
• Acts aimed at gaining profit through methods not intended by our company in relation to our service
• Advertising, promotion, solicitation, or business activities not authorized by our company on our service
• Collecting or accumulating personal information about other users
• Using our service for illegal, improper, or unjust purposes
• Acts causing disadvantage, damage, or discomfort to other service users or other third parties
• Impersonating other users
• Using other users' accounts
• Acts aimed at meeting unfamiliar persons of the opposite sex
• Acts directly or indirectly providing benefits to antisocial forces
• Acts violating public order and morals
• Using our service while walking, driving, or in other inappropriate situations or manners
• Other acts our company deems inappropriate

11. Prohibition of Monetization

The following transactions are strictly prohibited for all content or virtual currency acquired within our service, regardless of method:

• Buying and selling
• Any transfer, receipt, lending, borrowing involving monetary or other consideration
• Any other acts our company deems to constitute monetization

12. Exclusion of Antisocial Forces

Users represent and warrant that they do not and will not correspond to any of the following categories:

• Organized crime groups, their members, or related parties
• Entities controlled or substantially influenced by organized crime groups
• Those utilizing or maintaining relationships with organized crime groups
• Those providing funds or convenience to organized crime groups
• Officers or substantial participants having socially condemnable relationships with organized crime groups

13. Usage Restrictions

Our company may restrict all or part of service usage or delete user registration without prior notice if users correspond to any of the following. Our company bears no responsibility for damages caused to users by actions taken under this provision:

• Violation of any provision of these Terms
• Discovery of false information in registration details
• Non-performance of monetary obligations
• No response to our company communications after a reasonable period
• No service usage for a considerable period from the last usage date
• Determination of being antisocial forces or having交流 or involvement with such forces
• Other cases where our company deems service usage inappropriate

14. Service Suspension

Our company may suspend or interrupt all or part of service provision without prior user notice if we determine any of the following circumstances exist. Our company bears no responsibility for any disadvantage or damage suffered by users or third parties in such cases:

• Performing maintenance, inspection, or updates of computer systems related to our service
• Service provision becomes difficult due to force majeure such as earthquakes, lightning, fires, power outages, natural disasters, or virus outbreaks
• Computer or communication line stoppages due to accidents
• Other cases where our company deems service provision difficult

15. Account Termination

Users may delete their user registration and withdraw from our service through procedures designated by our company.

16. Warranty Disclaimer

Our company does not warrant that our service or content provided by our service is free from system bugs or third-party rights infringement. We also do not warrant safety, reliability, accuracy, completeness, effectiveness, or suitability for specific purposes.

17. Limitation of Liability

Our company bears no responsibility for any damages caused to users regarding our service. However, this disclaimer does not apply if contracts between our company and users regarding our service (including these Terms) constitute consumer contracts as defined by the Consumer Contract Act.

Even when applicable as consumer contracts, our company's liability is limited to direct, actual damages caused to users by our company's negligence (excluding gross negligence), with compensation capped at either one month's service usage fees or 10,000 yen, whichever is lower.

18. Service Changes

Our company may change service content or suspend/terminate service provision without user notification. Users agree without objection in advance that if our service terminates, they will lose all rights to use paid content and will no longer be able to use such paid content. Our company bears no responsibility for damages caused to users by these changes.

19. Terms Modifications

Our company may modify these Terms at any time without user notification. Modified Terms take effect from the time they are posted on our company website. Users who continue using our service after Terms modifications are deemed to have agreed to the modified Terms.

20. Personal Information Handling

Personal information acquired through service usage will be handled appropriately according to our company's Privacy Policy.

21. Contact and Communications

Communications between users and our company shall be conducted through methods designated by our company. Our company will regard currently registered contact information as valid unless change notifications are submitted according to separately designated procedures, and communications to such contact information are deemed delivered upon transmission.

22. Assignment of Rights and Obligations

Users may not transfer their position under usage contracts or rights/obligations under these Terms to third parties or use them as collateral without our company's prior written consent.

23. Business Transfer

When our company transfers business related to our service to other companies (including business transfers, company splits, and all other cases where business is transferred), we may transfer our position under usage contracts, rights and obligations under these Terms, and user information to the business transfer recipient. Users are deemed to have consented to such transfers in advance.

24. Governing Law and Jurisdiction

Japanese law shall govern the interpretation of these Terms.

In case of disputes regarding our service, the district court with jurisdiction over our company's head office location shall have exclusive agreed jurisdiction.

Contact Information

For questions about these Terms of Service, contact us at:

Email: kei.fujikawa@kboy.jp

Business Entity: KBOY Inc.
Representative: Kei Fujikawa
Address: 4-41 Midpoint Hatagaya, Keio Hatagaya Building, 1-2-2 Hatagaya, Shibuya-ku, Tokyo 151-0072, Japan

Established: March 28, 2024