Privacy Policy

1. Who we are

Shogi Analysis (the “App”; 将棋解析 in Japanese) is developed and run by Yusuke Kurokawa, an individual developer (“we” or “us”). This policy explains how we handle your information in the App and on this website. This English version is a translation of the Japanese original. If the two differ, the Japanese version prevails.

2. Information we collect

To provide game analysis and review, the App handles the following information:

• An ID that identifies your account.
• Your email address, if you choose to add one (used to confirm it’s you and to carry your data over, for example when you change phones).
• The game records you add, and the information in them, such as player names, the date and time of the game, and the moves.
• Analysis results, the problems created from your games, and your answers and review history.
• A device ID generated by the App, used to sync your records and avoid duplicates.
• A device identifier used to make sure the free plan’s daily limit isn’t reset by creating a new account (on Android, the device’s ANDROID_ID; on iOS, an ID the App generates and stores only on that device). Our servers store it only in a form that can’t be turned back into the original value.
• The App version, your operating system (iOS / Android), and the App’s display language.
• The contents of game records that couldn’t be read, and the reason they couldn’t be read.
• Records of how the App runs (details of any crashes or errors, and which screens and features you use).
• The status of your paid plan (plan type and expiry date). Payments are handled by the App Store / Google Play, and the App never receives your payment details.

Records of how the App runs are sent together with your account ID, the App version, your operating system and its version, and your device’s language settings. They don’t include the contents of your game records, player names or your email address. We don’t collect advertising identifiers (advertising IDs) or your device’s location (such as GPS). For usage records, your approximate location (country and city) is estimated from the IP address of your connection.

You don’t need to give us your name or email address to use the App. If you add an email address, you can sign in to the same account with a verification code sent to it. We never send advertising or promotional emails to that address.

3. How we handle your game records

We receive a game record when you choose a file, load it from the clipboard, or share it from another app. If you share the URL of a game on Shogi Wars, Shogi Quest, KIOU or 将皇 (a Japanese shogi app), our server fetches that one game from the game’s page. The App never fetches game records from game services automatically without an action from you.

To analyze them, the game records you add are sent to our server and stored together with their analysis results. When a game record can’t be read, for example because of its format, we keep its contents for a limited time so we can find the cause and support more formats.

When you tap Share on the analysis screen, we create a link to a page showing that one game’s record (including the players’ names, the moves and the date of the game) and its analysis results. Anyone who knows the link can view the page, even without the App. A shared page becomes unavailable when you delete your account. If you want to stop sharing a page while keeping your account, or if a shared page shows one of your own games and you want it taken down, please contact us. However, images and text shown on the social network or other service the link was shared to may remain there after the page becomes unavailable. For each shared page, we count per day how many times it was viewed, the type of referrer (such as which social network), and how many times the buttons on the page were tapped. We store only these counts, and nothing that identifies the people who viewed the page.

You can delete your account from the Account screen in the App. This deletes the game records, problems and review history linked to your account, and your sign-in account, including any email address you added. Analysis results that consist only of board positions and evaluations may be kept as a shared cache, separated from anything that identifies you. However, to prevent misuse of the free plan’s limits, the converted device identifier, together with the IDs of the accounts used on that device, when they started being used and were deleted, and that day’s usage counts, is kept after you delete your account for the period set out in “6. How long we keep your information”.

4. How we use your information, and our legal bases

We use the information we collect to analyze your games, create problems, provide paid plans, schedule your reviews, store and sync your data, show the pages of games you share, manage your account, respond to your inquiries, investigate outages and bugs, prevent misuse, improve the App and explore new features, and run and improve this website. We don’t use it beyond these purposes.

To investigate outages and bugs and to improve the App, we may look at stored game records, analysis results and usage records. We never publish anything we see in a way that could identify you.

Our legal bases for handling your information are as follows. Analyzing your games, creating problems, providing paid plans, scheduling your reviews, storing and syncing your data, showing the pages of games you share, and managing your account are necessary to perform our contract with you to provide the App (our Terms of Use). Responding to your inquiries, investigating outages and bugs, preventing misuse, improving the App and exploring new features, and serving this website and the pages of shared games (including their fonts) and measuring their traffic are based on our legitimate interests in running the App and this website safely, making them better, and answering your questions. Anything we do because the law requires it is based on our legal obligations.

5. Sharing with third parties

We don’t share your information with third parties without your consent, except where required or authorized by law. A page you create by tapping Share (see “3. How we handle your game records”) is made public by your own action.

We use the following external services to provide the App. Information is stored on each service’s servers. The country after each dash is where the company running the service is based.

• Supabase (data storage and sign-in) — Singapore
• Amazon Web Services (our API, game analysis, and sending verification codes and replies to inquiries by email via Amazon SES) — Japan
• Expo (delivering App updates) — United States
• RevenueCat (verifying paid plan purchases) — United States
• Cloudflare (serving this website, the pages of shared games and our admin dashboard, traffic analytics for this website and the pages of shared games, and forwarding emails sent to our support address) — United States
• Sentry (crash and error reports) — United States
• PostHog (App usage records) — United States
• Google (fonts for this website via Google Fonts, and sending and receiving support emails via Gmail) — United States

Of these, our Supabase database, and our API and game analysis on Amazon Web Services, are hosted on servers in Japan (Tokyo). Sentry and PostHog store information on servers in the United States. In these companies’ operations and in relaying network traffic, and in the other services, your information may be handled outside Japan, including in the United States.

This website and the pages of shared games (share.shogi-ai.jp) use Cloudflare Web Analytics, provided by Cloudflare, Inc., to understand how they are used and improve them. When you view a page, the page’s URL, the referring URL, your browser, operating system and device type, and how long the page took to load are sent to Cloudflare. No cookies are used, and you are not identified or tracked as an individual. For how Cloudflare handles information, see Cloudflare’s privacy policy.

6. How long we keep your information

Game records, analysis results, problems and review history are kept for as long as your account exists, and are deleted when you delete your account. A share link stays valid for as long as your account exists, and is deleted when you delete your account (unless we have stopped publishing the page after being contacted).

The contents of game records that couldn’t be read are kept for up to 90 days and then deleted. If you delete your account, they are deleted at that point.

To recover from failures, we keep database backups for up to 7 days. Server logs (access and error records) are kept for up to 90 days to investigate problems and prevent misuse, and then deleted.

Records of how the App runs are kept for up to 30 days for crash and error reports and up to 1 year for usage records, and then deleted.

The converted device identifier, and the IDs of the accounts used on that device with the times they started being used and were deleted, are kept for up to 1 year after the device was last used, and then deleted. They are kept for this period even if you delete your account. Each device’s usage counts for the day are deleted once the next day has passed.

7. Your rights

You can ask us to give you access to the information we hold about you (including a copy of your data), to correct or delete it, to stop using it or restrict how we use it, and to give you the data you provided to us in a machine-readable format so you can move it to another service (data portability). You can also object to any handling based on our legitimate interests. You can delete your account, along with the game records, problems and review history linked to it, yourself from the Account screen in the App. For any other request, please contact us using the details below. Once we have confirmed that the request comes from you, we will respond in accordance with applicable law.

If you are unhappy with how we handle your information, you can lodge a complaint with the supervisory authority in your country or region (in Japan, the Personal Information Protection Commission; in the EU or the UK, the data protection authority in your country).

8. Changes to this policy

If we change this policy, we will post the updated version on this page. By using the App or this website after a change, you agree to the updated policy.

Established and effective: September 16, 2026
Revised: September 19, 2026 (added receiving game records shared from other apps, keeping game records that couldn’t be read, collecting the App version, investigating outages and improving the App as purposes of use, and optional email registration with verification codes)
Revised: September 25, 2026 (added paid plan status and RevenueCat for verifying it, traffic analytics for this website [Cloudflare Web Analytics], and records of how the App runs [crashes, errors and usage] with Sentry and PostHog for recording them)
Revised: October 17, 2026 (added legal bases, the countries of the companies running our external services and where your information is handled, your rights, and this English version; also covered fetching games from Shogi Quest and KIOU URLs, the App’s display language and your device’s language settings, estimating approximate location from IP addresses, responding to inquiries, preventing misuse and serving this website as purposes of use, Google [fonts and support email], serving our admin dashboard and forwarding support emails as uses of Cloudflare, and game analysis and replying to inquiries via Amazon SES as uses of Amazon Web Services)
Revised: October 27, 2026 (added the device identifier used to prevent misuse of the free plan’s limits, and keeping its records after you delete your account)
Revised: November 9, 2026 (added fetching games from 将皇 game URLs)
Revised: November 10, 2026 (added links for sharing a game, and serving and measuring the traffic of the pages of shared games)
Revised: November 11, 2026 (changed how to stop sharing a page: by contacting us or deleting your account)

9. Contact

For questions about this policy, please email us at support@shogi-ai.jp (English is fine) or use our contact page.