プライバシーポリシーPrivacy Policy

This Policy sets out how kokushing (the “Operator”) handles users' personal information in the application “Yu's Sleep” (the “App”). The Operator's name and address will be disclosed without delay in accordance with the “Legal Notice (Specified Commercial Transactions Act),” or upon a request based on law.

The App handles the following information in order to provide the service.

• An identifier for anonymous authentication (an ID automatically issued when the App is launched)
• Sleep records (bedtime and wake times, time to fall asleep, sleep cycles, recording-related settings, and so on). In principle these are stored on the device and may be sent to the server for backup and synchronization across multiple devices.
• Information about your use of Chat (text chat with Yu): the text of the messages you enter, the text of Yu's replies, the situation you select, your affinity level, which situations you have unlocked, and records of Sleep Points spent. This information is stored on the server. See “About Chat (Talking with Yu)” below for details.
• If you link an account, the email address and account identifier provided by Apple or Google (used for data transfer)
• Information about the purchase and subscription status of the Support Plan (processed through the payment provider; the Operator does not collect payment information such as credit card numbers)
• Information you provide when contacting us
• Usage records (events indicating which features of the App are used, recorded together with a pseudonymous ID linked to your anonymous account; see “Usage Records (Analytics for Product Improvement)” below for details)
• Information automatically recorded regarding the App's operation (such as server access times and error information). This is a minimum record for troubleshooting; we do not collect information for advertising or for tracking by third parties.

The nickname Yu uses for you is stored only on your device and is never sent to the server. The text stored for chats and sleep records does not contain the nickname itself; it is filled in on your device when the text is displayed.

The Operator uses the collected information for the following purposes.

• Providing, maintaining, and improving the App
• Storing sleep records and synchronizing them across devices
• Transferring accounts (e.g., when changing devices)
• Providing the Support Plan and verifying subscription status
• Generating Yu's comments
• Providing Chat (talking with Yu): generating replies, storing and displaying the conversation history, managing affinity, unlocked situations, and Sleep Points, and preventing abuse or excessive use
• Improving features and identifying issues based on usage records (product analytics)
• Identifying and addressing issues and improving quality
• Responding to inquiries from users
• Responding as required by law

To improve the App's features and identify issues, the Operator records signals indicating which features of the App a user uses (“usage records”). These records are used solely for the Operator's own (first-party) analytics; we do not use any third-party analytics or advertising SDKs such as Firebase or Google Analytics.

The usage records consist of the following information.

• Event names and their accompanying properties (feature-usage signals only)
• The platform (iOS / Android / Web), the app version, and the time of occurrence (on the device and on the server)
• A pseudonymous ID linked to your anonymous account (the Supabase anonymous user ID; it is not associated with your name, email address, or the like)

Examples of the events we record include the following.

• Launching or resuming the App; completing or skipping onboarding
• Starting, completing, or canceling sleep (the type [night / short rest], the sleep duration in minutes, the number of sleep cycles, and whether a bedtime bonus applied)
• Whether an alarm is set, and the on/off state of the bedtime reminder
• Viewing the Support Plan screen; completing a purchase or restore
• Playing a work (video) (the work ID and its free/premium classification); selecting an ambient sound (the type of sound and its free/premium classification)
• Account linking (with either Apple or Google)
• Use of Chat (sending a message [situation ID and affinity tier], unlocking a situation [situation ID and points spent], and resetting your chat data)

We do not collect the following as part of usage records.

• The contents of your sleep records (any detail beyond the coarse indicators above), or text such as your chat conversations and the comments generated by Yu
• Your name, email address, authentication tokens, device identifiers, advertising ID (IDFA), exact bedtime/wake times, location, or contacts

Usage records are used only to improve the App's features and to identify issues (product analytics). The Operator does not provide or sell usage records to third parties. Nor do we use them for cross-app or cross-site tracking or for advertising purposes. Like other user data, usage records are stored in the backend the Operator uses (Supabase); we have not added any new external vendor for this analytics.

You can turn usage records off at any time from “Settings → ‘Usage recording’” in the App (they are on by default). Once turned off, no usage records are sent thereafter.

Usage records are automatically deleted in conjunction with the deletion of your account. In addition, the Operator may delete them on a rolling basis after a certain period.

→ See Account Deletion for how to request deletion of your data.

The App uses the following external services to provide its functions. To some of these services, it entrusts the handling of information to the extent necessary.

• Supabase (authentication, data storage, and storage of usage records; the server is operated in the Japan (Tokyo) region)
• Apple (App Store) / Google (Google Play) (payment and billing for in-app purchases, and account linking via sign-in)
• RevenueCat (management of Support Plan subscription status; handles the anonymous account identifier and purchase information)
• Cloudflare (delivery of video content; the Operator does not provide users' personal information)
• Google (Gemini API; for generating Yu's comments, numerical and time information about sleep is sent. For the Chat feature, the text of the messages you enter, the recent conversation history for the same situation (up to 20 messages), and a summary of your sleep as background for the conversation (the duration and type of your most recent sleep and your average sleep over the past 7 days) are also sent. In neither case do we send your name, email address, account identifier, or nickname.)
• YouTube (retrieval of Google's public data; the Operator does not provide user information)

Among these, the handling of personal data may be entrusted to third parties located outside Japan, such as RevenueCat (United States). Information about the personal information protection systems of such foreign countries and about the security measures taken by the entrusted parties will be provided upon request to the contact below. The handling by each service is also subject to the privacy policy established by each provider.

Chat is a text-chat feature with Yu available to Support Plan subscribers. Yu's replies are automatically generated by generative AI (Google's Gemini API); they are not the statements of a real person.

This feature handles information as follows.

• The text of the messages you enter and Yu's replies are stored on the server (Supabase) so that the conversation can be continued and displayed. Stored content is managed through access controls (row-level security) so that, in principle, only you can view it.
• To generate a reply, the text of your message, the recent conversation history for the same situation (up to 20 messages), and a summary of your sleep as background for the conversation are sent to Google (Gemini API). Your name, email address, account identifier, and nickname are not sent.
• Your affinity level, which situations you have unlocked, and records of Sleep Points spent are stored.
• To prevent excessive or improper use, the number of messages sent within a given period is recorded.

Please do not enter information that identifies you or another person — such as names, contact details, or addresses — or sensitive information such as health or beliefs. As described above, what you enter is stored on the server and sent to an external service in order to generate a reply.

You can delete your conversation history and affinity at any time from “Settings → ‘Reset chat’” in the App. That operation does not delete the situations you have unlocked or the records of Sleep Points spent (deleting them would return your points and allow situations to be unlocked repeatedly). If you want everything deleted, please delete your account. Chat-related information is automatically deleted in conjunction with the deletion of your account.

→ See Account Deletion for how to delete your account and data.

Except in the following cases, the Operator does not provide personal information to third parties without obtaining the user's prior consent.

• Where required by law
• Where necessary to protect a person's life, body, or property and it is difficult to obtain the person's consent
• Where we entrust the handling of information to the external services described above, to the extent necessary to achieve the purpose of use

The Operator does not sell or provide users' personal information to third parties for advertising or other purposes.

The Operator takes necessary and appropriate measures to prevent the leakage, loss, or damage of the information it collects. Authentication information (such as access tokens) is stored in the device's encrypted secure area (the iOS Keychain / Android Keystore). Information stored on the server is managed through access controls (row-level security) so that, in principle, only the person concerned can view it, and communications use encrypted channels.

The collected information is retained for the period necessary to achieve the purpose of use. In addition to deleting the App's data on the device, if you wish to delete your account and the data on the server, please contact us using the contact information below. The Operator will respond to deletion without delay, except where otherwise provided by law.

→ See Account Deletion for how to delete your account and data.

Users may request the Operator to notify the purpose of use of, disclose, correct, add to, or delete the content of, and to suspend the use of, erase, or suspend the third-party provision of, their retained personal data. Requests are accepted at the contact information below. We may confirm that a request is made by the person concerned.

The Operator may revise this Policy in response to changes in laws, changes to the service, and so on. When making a material change, the Operator will provide notice by display within the App or by other appropriate means.

Inquiries regarding the handling of personal information in the App, requests for disclosure, and the submission of complaints are accepted at the following point of contact.