GETTYS L JASON (trade name: Jason Kobayashi) operates Mastermind Japanese. Business mailing address: RJ3, 2-16-12 Jiyugaoka, Meguro-ku, Tokyo 152-0035, Japan. Privacy and support requests should be sent to support@mastermindjapanese.com.

• Account email, authentication data, optional password hash, and Google sign-in identifier if used.
• Study progress, answers, session history, bookmarks, kanji writing progress, and settings.
• Feedback submissions and attached screenshots when the user submits them.
• Support requests, including reply email, category, impact, subject, message, optional page/browser details, and optional account association when signed in.
• Operational logs such as IP address, user agent, timestamps, and security-relevant request metadata.

Data is used to provide accounts, study features, support, fraud prevention, abuse prevention, security, and product maintenance. Support request notifications may be sent through our transactional email provider so the operator can respond. We use carefully selected service providers for hosting, data storage, transactional email, and optional third-party sign-in.

Account and study data are kept while the account is active unless deletion is requested or retention limits are introduced for reliability, cost control, or abuse prevention. Support requests are retained as operational records long enough to resolve user issues and handle billing, security, legal, or accounting follow-up where needed. Users may request access, correction, deletion, restriction, objection, or portability where applicable. Reasonable safeguards are used, including HTTPS, password hashing, access controls, limiting email-address exposure in routine product and operator views, using account handles where practical, and regular security/dependency review. No system can guarantee absolute security.