Contact

Questions, bug reports, ideas for new worksheets, privacy requests or partnerships — we read every message.

study@eidendo.co.jp

What helps us answer quickly

• The page or worksheet you were using (a link is perfect)
• Your device and browser, or the AI service you used
• What you expected and what happened instead (a screenshot helps)

Please don't send

Passwords, payment details, or personal information about a learner such as a child's full name. We never need them.

Operator

Eidendo Inc. / Study River (Japan). We usually reply within a few business days, in English or Japanese.