Privacy Policy
Last updated: 7 November 2026 (Japanese original). English translation updated 7 November 2026.
This is an English translation of the Japanese privacy policy. If the two differ, the Japanese version prevails.
1. Introduction
yorozu-craft ("this site") respects your privacy and works to protect personal information. This privacy policy applies to every tool published on this site.
2. Information we collect
The operator of this site does not collect information that identifies you, such as your name, email address or phone number. Every tool does its calculations and processing inside your browser, and never sends what you enter to the operator or to any external server.
Messages sent to our LINE Official Account (7.5) are processed on a server to reply to them, and are not stored. Text sent through the suggestion box (7.6) is stored on a server. Text you paste into the plain Japanese rewriter and speech you give to the "enter by voice" button in our calculators (7.7) are processed on a server and are not stored. Bingo "play together" (7.9) keeps the list of called numbers on a server for 3 hours.
3. Data stored in your browser
For convenience, some tools save settings, input or history in your browser (local storage). This data stays in your browser and is never sent anywhere. Clearing your browser's site data deletes it. Each tool's guide page states what it stores. You can also delete it with the “Delete everything saved (reset)” button on each tool's screen.
To delete what every tool on this site has saved, all at once, press this button (data from other sites is not affected).
So that they work where the connection is poor, some tools use a mechanism called a Service Worker to store the tool's own files (pages, styles, programs, images) in your browser. Only the tool's files are stored, not your input or a record of what you did.
4. Use of device features
Tools that use a device feature such as location ask for permission through your browser only when you perform the action that needs it. You can still use the tool in other ways if you decline. The information is used only for that tool's calculation and is not sent anywhere. If a tool saves your location, it saves only a value with reduced precision.
5. Share links
In tools that let you share a result, the share link may contain the input needed to open the same result. Anyone who receives the link, and the service used to send it (a messaging app, for example), can then see that input. The input is placed after the "#" in the URL, so opening the link does not send it to this site's server. If you do not want to share real names, enter a nickname instead.
6. Cookies and tracking
The tools themselves do not use cookies. Our analytics (7.3) are also cookie-free. However, Google may use cookies to serve ads (7.1).
7. Third-party services
7.1 Google AdSense
This site uses Google AdSense to serve ads. Third-party vendors, including Google, may use cookies to serve ads based on your prior visits to this site or other websites. Some pages, such as full-screen tool screens, show no ads.
For details, see Google's advertising policies. You can turn off personalized ads in Google's Ad Settings. You can also opt out of third-party vendors' cookies used for personalized advertising at youradchoices.com.
7.2 Cookie consent (visitors from the EEA, the UK and Switzerland)
Visitors from the European Economic Area (EEA), the United Kingdom and Switzerland see a message from a Google-certified consent management platform (Google's consent management tool) asking for consent to the use of cookies and similar technologies for advertising.
The message offers "Consent", "Do not consent" and "Manage options". If you do not consent, every tool still works as usual (ads may be limited or not shown). Visitors from other regions do not see this message.
7.3 Analytics
To understand how the site is used and to improve it, this site uses Cloudflare Web Analytics, provided by Cloudflare, Inc. It does not use cookies or local storage, and it does not collect information that identifies you or that could be used to track you across sites. It collects statistical information such as the pages viewed, the referrer, the browser, operating system and device type, the country or region, and page load speed. What you enter into the tools is not collected.
For details, see Cloudflare's privacy policy.
Only when the top page is opened from the home screen ("Add to Home Screen"), we send the page location (/) and a mark saying it was opened from the home screen to a Cloudflare, Inc. server (Workers Analytics Engine) to count such opens. We do not send what you enter, cookies or device information.
When you press a link visible on the first screen of the top page, we send only the location of the page you go to and a mark saying "from the first screen" to the same server to count such clicks.
To show the "next revision" line, the top page loads the revision date from this site's calculation API (Cloudflare Workers). Nothing is sent from your side.
When you press the button to download the free printable PDF (/print/), we likewise send only the PDF location and a mark saying "download" to the same server to count downloads.
When you use a tool and it first shows a result, we send only the page location and a mark saying "used" to the same server to count how often tools are used (once per page view; what you enter and the result are not sent).
7.5 LINE Official Account (LINE version)
When you send a message to our LINE Official Account, a program on Cloudflare, Inc.'s servers replies using the same calculations as this site. We do not store the messages you send, your LINE user ID, or our replies. The only thing we store is the number of replies, AI uses, voice messages and photos that day (for a daily limit; it is deleted the next day). We never send messages on our own; we only reply. Messages that do not match our example formats may be passed to Cloudflare, Inc.'s AI (Workers AI) only to work out which calculation you are asking about. Neither the message nor the AI's output is stored, and Cloudflare does not use them to train AI models. Voice messages are passed to Cloudflare, Inc.'s AI (Workers AI) to convert them into text. We do not store the audio. Photos you send are passed to the same AI to read the text in them and rewrite it in plain Japanese. We do not store the photo, the text read from it or the rewritten text.
Messages pass through LINE's servers, operated by LY Corporation. For how LINE handles them, see LY Corporation's privacy policy.
7.6 Suggestion box
Text sent through our suggestion box (in Japanese) is stored on Cloudflare, Inc.'s servers (Cloudflare D1), and the operator reads it only to make and improve the tools. We store the text, the date and time, which page you came from (the page path only) and the page language. We do not store your IP address, browser information, cookies, name or contact details. Stored text is deleted automatically after one year. Please do not include your name or contact details; we do not reply. The operator may sort stored messages with an AI tool (Cloudflare Workers AI); they are not used for training.
To prevent automated mass submissions, Cloudflare Turnstile (Cloudflare, Inc.) checks each submission, and Cloudflare may temporarily block repeated submissions in a short time (the operator does not store the information used for this). For how Turnstile handles data, see Cloudflare's privacy policy.
7.7 Plain Japanese rewriter and voice input
Text you paste into the plain Japanese rewriter (in Japanese) is passed to an AI on Cloudflare, Inc.'s servers (Workers AI) to rewrite it. We do not store the text you paste or the rewritten text, and Cloudflare does not use them to train AI models. The only thing we store is the number of uses that day (for a daily limit; it is deleted the next day). Please remove names, addresses and other details that could identify a person before pasting. When you use a photo of a notice, the photo is also passed to the same AI and is not stored. When you have the text translated into another language, the rewritten text is also passed to the same AI and is not stored. When you have the text read aloud, your device's own speech function (the browser's speech synthesis) reads it. The text does not leave your device, and neither the text nor the audio is stored.
When you press "enter by voice" in our calculators (high-cost medical expenses, starting the pension early or late, and the medical expense deduction) and speak, your speech is passed to the same AI to turn it into text and read the values for the input fields. We do not store the speech, the text or the values. The microphone is used only after you press the button. The values only go into the input fields on the screen; please check them before you calculate. Everything else you enter still stays on your device.
7.8 Email (Cloudflare Email Routing)
Email sent to the operator's address (hello@yorozu-craft.com) is forwarded to the operator's mailbox by Cloudflare Email Routing (Cloudflare, Inc.). Cloudflare only forwards the email and does not store it. For how forwarding is handled, see Cloudflare's privacy policy.
7.9 Bingo: play together
When you open a room in the bingo caller, a room is created on a Cloudflare, Inc. server (Durable Objects) so that the numbers the caller draws also appear on players' phones. The room stores only the list of called numbers, the number range, the time it was created, and how many players reported a bingo. It is deleted automatically after 3 hours (or as soon as the caller closes it). Names, cards, IP addresses and browser information are not stored in the room. Each player's card is made on their own phone and is not sent. To count how many rooms one connection has open at the same time, the IP address is used only in the server's memory and is not stored.
7.10 Ask by email
When you send an email to kiku@yorozu-craft.com, a program on Cloudflare, Inc.'s servers reads it in the same way as the LINE version (7.5), does the same calculations, and replies only to the address that sent it. Only the first 2,000 characters of the message are read, and attachments are not read. We do not store the email you sent, your email address, or our reply. The only things we store are the number of emails and AI uses that day and the number from each sender that day (for a daily limit; each sender is counted by a code made from the email address, and the address itself is not stored; these counts are deleted the next day). Messages that do not match our example formats may be passed to Cloudflare, Inc.'s AI (Workers AI) only to work out which calculation you are asking about, and neither the message nor the AI's output is stored. Apart from replies, we do not send emails. Emails pass through Cloudflare Email Routing (7.8).
7.11 Finding similar tools (top-page search, LINE version, email)
When you type 3 to 200 characters in the search box on the top page and stop typing, we send that text to Cloudflare, Inc.'s servers. Cloudflare, Inc.'s AI (Workers AI) then finds the 3 tools closest in meaning, and we show them below the tools that match by name. When your words are a tool's name (or the start of one), nothing is sent. We count how many times the search is used and how many times someone opens one of the closest tools, recording only the page address (the text you typed is not sent for this count). In the LINE version (7.5) and by email (7.10), when a message does not match any of our example formats, its first 200 characters are used in the same way, and the 3 closest tools are added before the usage guide in the reply. We do not store the text you sent or the numbers made from it (embeddings). The only things we store are the number of searches that day (for a daily limit; deleted the next day) and a count marked only with whether the text was Japanese or English.
8. Children's privacy
This site does not knowingly collect personal information from any user, including children. When a child allows a feature such as location, a parent or guardian should check it with them.
9. Changes to this policy
This site may update this privacy policy when necessary. Any changes will be posted on this page.