Terms of Service

Established: October 22, 2026 / Last revised: October 23, 2026

This is an English translation of the Japanese Terms of Service (利用規約) at https://physdraft.com/terms. If the Japanese version and this English version differ in any way, the Japanese version prevails.

These Terms of Service (the "Terms") set out the conditions for using the learning service "PhysDraft" (the "Service"), provided by PhysDraft (the "Operator"). People who use the Service ("Users") must read these Terms and agree to them before using the Service.

Article 1 (Scope)

1. These Terms apply to all relations between the Operator and Users concerning the use of the Service.
2. The Service is a learning service in which, when a User uploads an image of a high-school physics problem, an AI reads the problem and creates a simulation that reproduces the situation in it. The app is provided at https://open.physdraft.com/. The homepage (https://physdraft.com/) is for introduction only and has no account or upload function.
3. Price lists, notices and usage explanations that the Operator posts on the Service or the homepage form part of these Terms. Personal information is handled in accordance with the Privacy Policy (Article 11).
4. When a corporation such as a school, cram school or company uses the Service (the business plans and the business free trial), it follows the conditions that the Operator and the corporation agree separately, in addition to these Terms. If they conflict with these Terms, those separate conditions take precedence.
5. The Service is currently a closed beta (invitation only). The content, prices and these Terms will change toward the open beta and the official release.

Article 2 (Accounts)

1. A User registers an account by entering a display name and creating a "passkey" on their device, or creates an account by logging in with Google. Passwords are not used. When registering with a passkey, e-mail addresses are not used either. When you log in with Google, the Operator receives Google's internal ID number, e-mail address and name from Google (handled in accordance with the Privacy Policy). The private key of the passkey and fingerprint or face information are not sent to the Operator (they stay on the device).
2. The display name does not have to be your real name. You may not use a name that impersonates another person, a name that offends others, or any other name that the Operator judges inappropriate.
3. A User who registers through an invitation link issued by the Operator can start as an "approved user". A User who registers without an invitation link becomes "pending", and can use the Service fewer times (the number is shown on the Service's screen). One invitation link can be used by one person only. You must not give your invitation link to another person.
4. Users manage their own accounts and passkeys (and, for Users who log in with Google, their Google accounts). You must not let others use your account, or lend or transfer it. One person must not create multiple accounts to exceed the usage limit.
5. If you lose your device, you can log in with a passkey you created on another device, or with the Google account you have connected. If you lose all of your ways to log in, the Operator will try to help, but recovery of the account is not guaranteed. We recommend creating passkeys on more than one device, or connecting Google.
6. Users under 18 must obtain the consent of a person with parental authority (a guardian) before using the Service. If a User under 18 uses the Service without obtaining that consent, the consent of the person with parental authority is regarded as having been given at the time of use.

Article 3 (Fees, Usage Limits and Payment)

1. Currently (closed beta), the Service is free of charge. Paid plans are not yet offered.
2. The Service has a limit on the number of times a User can send a problem and create a simulation.
   • The limit is shown on the Service's screen. In the closed beta it is a number of times per week, which resets at 0:00 on Monday (Japan time).
   • One time means creating one simulation for one problem. There is currently no limit on how many times you can play back a simulation that has been created.
   • The count is not restored if the creation fails (including cases where the AI could not reach an answer, the image could not be read, or processing stopped with an error), or if you later delete the problem you sent.
3. When paid plans start, the Operator will clearly show on the Service's screen the contents of the plan, the price (tax included), the number of times, the payment method, the payment timing, and how to cancel and obtain a refund. A paid-plan contract is formed only when the User checks that information and applies by their own action. Unless you apply, you are never switched automatically to a paid plan.
4. The price lists on the homepage (for students and for businesses) show what is planned for when paid plans start. The actual contents follow the information shown under the preceding paragraph.
5. The free trial planned for the open beta lets you try a certain number of times (planned: the first 10 times for students) for free when you first use the Service. The students' free trial is available once per account, and its count does not reset after a week. The business free trial (planned: the first 30 times) is available once per corporation. Neither free trial switches automatically to a paid plan. The conditions of the free trial will be shown on the Service's screen when it starts.
6. The conditions for cancelling a paid plan and for refunds will be set and shown when paid plans start.
7. The Operator may change the number of times, the prices and the contents of plans. When it does, it will announce the change on the Service's screen before the change takes effect.

Article 4 (Problems You Upload)

1. A User can upload and send images of problems (currently PNG, JPEG and WebP; up to 8 images at a time, up to 10 MB each).
2. Before sending a problem, you must make sure that you are permitted by the right holder, or that it is within the scope allowed by law, for the Operator and the businesses named in the Privacy Policy to use the problem in order to provide the Service (including storing, copying, sending to an AI, and displaying it). When you send copyrighted material such as textbooks, problem collections, past exam questions, mock exams, or worksheets from schools and cram schools, you must check by yourself whether the right holder's permission is necessary. You must not send a problem that you have no right to use.
3. The copyright and other rights in the problems you upload remain with the original right holders. The Operator does not acquire these rights. The Operator uses the uploaded problems to the extent necessary to provide the Service (storing, sending to an AI, displaying on the screen, investigating defects), and for the purpose in the next paragraph.
4. The Operator looks at the problems sent and uses them to improve the Service's engine and AI (the instructions and the mechanism), and to check the accuracy of results. The Operator does not currently use the problems sent to train AI models themselves (for example, fine-tuning). For the external AI gateway (OpenRouter), the Operator also uses a setting that does not use providers that use paid usage content to train models.
5. Please make sure that no personal information of yourself or others (such as names, face photos, addresses, answer sheets or name lists showing a school name) appears in the images you upload. Photos taken with a smartphone may contain information such as the shooting location (Exif). The Service stores the original of the uploaded image as it is, and also sends it to the AI. Photograph only the part of the problem and turn off location information so as not to send unnecessary information.
6. A User can delete the images and results of a problem they sent at any time with "Delete this problem" on the screen (a problem that is still being solved can be deleted once it has finished). Deleted images and results cannot be restored. Even if you delete a problem, the record of the count and the usage information that the Operator has recorded (the model used, the cost, etc.) remain.
7. If the Operator judges that an uploaded problem falls under Article 5 or may infringe others' rights, it may delete it without notifying the User.

Article 5 (Prohibited Acts)

Users must not do any of the following.

1. Acts that violate laws and regulations or public order and morals
2. Acts that infringe others' copyrights, portrait rights, privacy or other rights (including uploading, without the necessary permission, a problem you have no right to use or an image showing others' personal information)
3. Uploading images unrelated to physics problems, or obscene, violent or discriminatory images
4. Using another person's account or passkey, impersonating another person, lending or borrowing accounts, or creating multiple accounts to avoid the usage limit
5. Placing an excessive load on the Service's servers or network; making large-scale access with automated programs (bots, scraping, etc.) or calling the Service by means other than the screens the Operator provides
6. Unauthorized access to the Service, the Operator's systems or external services; searching for vulnerabilities or attacking them without the Operator's permission; reverse engineering
7. Trying to manipulate the mechanism of the Service improperly, for example by writing instructions to the AI inside an image
8. Collecting the Service's output in large quantities without the Operator's permission in order to build a competing service or training data for AI
9. Acts that cause disadvantage, damage or discomfort to the Operator, other Users or third parties
10. Any other act that the Operator judges inappropriate

Article 6 (Generated Content and Intellectual Property)

1. Users may use the simulations, answers, explanations and the like that the Service creates (the "Generated Content") for study and lesson preparation.
2. Rights in the part of the Generated Content that corresponds to the original problem (the text and figures of the problem) remain with the original right holders. If you publish, distribute or sell the original problem contained in the Generated Content, you must obtain the right holder's permission at your own responsibility.
3. Because the Generated Content is created by AI, it may resemble other content. The Operator does not guarantee that the Generated Content does not infringe third parties' rights.
4. Rights in the mechanism of the Service (the engine, screens, instructions, logo, etc.) belong to the Operator or to those who have licensed them to the Operator. The Operator grants Users no right other than the right to use the Service in accordance with these Terms.
5. The extent to which a business plan can be used, for example to show content during a lesson, follows the plan's description and the conditions in Article 1, paragraph 4.

Article 7 (About the Results of the AI)

1. The Service uses AI to read the image of a problem, create the situation of the problem as a simulation, and output an answer and an explanation. The AI may misread the problem, give a wrong answer or explanation, reproduce a figure or conditions incorrectly, create a simulation whose motion differs from the original problem, or be unable to create a simulation (including when the engine lacks a necessary component).
2. The Service is a beta version. It currently targets mainly mechanics problems. Problems in other fields and complex problems may not be handled correctly.
3. The results of the Service are meant to help your study. Do not use them as they are as the basis for answer sheets, homework, examinations, entrance examinations, grading, research or safety-related decisions. Always check them with textbooks, the answers in problem collections, a teacher, etc.
4. The Operator does not guarantee that results are correct, match the problem, or are useful.
5. To produce better results, the Operator may change the AI model, the engine and the instructions without notice. The result for the same problem may differ depending on the time.

Article 8 (Changes, Interruption and End of the Service)

1. The Operator may change the content, functions, usage limits and prices of the Service, and may interrupt or end all or part of the Service, after notifying Users (in an emergency, by notifying afterwards).
2. The Operator may interrupt the Service without prior notice in the following cases: system maintenance, failures, power outages, natural disasters, failures or specification changes of external services (such as cloud and AI providers), and other unavoidable cases.
3. The Operator does not back up Users' data. If the problems or results you sent disappear, they may not be recoverable. Please save what you need by yourself.
4. When the Operator ends the Service, it will notify Users with reasonable advance notice. After the end, the Operator may delete the data it holds.

Article 9 (Restrictions, Account Deletion and Withdrawal)

1. If a User falls under any of the following, the Operator may, without prior notice, restrict their use (change or suspend the number of times), delete the problems and Generated Content they uploaded, and delete their account.
   • When the User has violated these Terms or is likely to
   • When the registered information contains falsehoods
   • In other cases where the Operator judges it inappropriate for the operation of the Service
2. A User can withdraw at any time by contacting the Operator (Article 12). Currently, the app has no function for withdrawing from the screen. Before withdrawing, please delete the problems you sent with "Delete this problem" on the screen.
3. When it receives a withdrawal request, the Operator will delete the account information (display name, passkeys, Google connection, icon, record of days of visit). If the images and results of the problems you sent remain without having been deleted with "Delete this problem", the Operator will delete them when you ask. This deletion requires work by the Operator and may take time. Records of counts, costs and the like in a form that does not identify the User may remain.

Article 10 (Disclaimer and Limitation of Liability)

1. The Operator does not guarantee that the Service is free of defects in safety, reliability, accuracy, completeness, effectiveness, fitness for a particular purpose, errors or bugs, or that it does not infringe others' rights.
2. The Operator is not liable for damage caused to Users by any of the following, except where the Operator is intentionally or grossly negligent.
   • Errors in the Service or in the results
   • Interruption, delay or end of the Service, or loss of data
   • Unauthorized use by third parties due to insufficient management of the User's device, passkeys or account
   • Failures or specification changes of the services of external providers (such as cloud and AI providers)
   • Disputes arising from the problems that the User sent infringing others' rights
3. Even where the Operator is liable, except where it is intentionally or grossly negligent, the damages the Operator pays are limited to ordinary direct damage actually incurred by the User. For Users of paid plans, the upper limit is the total of the fees the User paid to the Operator during the 12 months before the month in which the damage occurred.
4. This Article applies, where the User is a consumer under the Consumer Contract Act, only to the extent permitted by that Act.
5. Disputes between a User and other Users or third parties are to be resolved by the parties themselves. If a User causes damage to the Operator by violating these Terms, the User compensates the damage.

Article 11 (Handling of Personal Information)

Users' personal information is handled in accordance with the Privacy Policy (https://physdraft.com/en/privacy; if the English version differs, the Japanese version at https://physdraft.com/privacy prevails). Please check the contents of the Privacy Policy (including that images of problems are sent to an AI gateway operated by a business abroad) before using the Service.

Article 12 (Contact and Notices)

1. Please contact the Operator by e-mail at physdraft@gmail.com. A reply may take some time.
2. The Operator gives notices to Users by posting them on the Service's screen or the homepage. A notice is regarded as having reached Users at the time it is posted.
3. The Operator receives the e-mail address of a User who logs in with Google, but uses it only to confirm which Google account is connected, and not to contact the User. Because the Service does not collect the e-mail addresses of Users who log in with a passkey, the Operator cannot contact Users individually by e-mail. The Operator may contact them by a means through which the Operator and the User are already in touch, such as the channel through which the invitation link was handed over.

Article 13 (Changes to These Terms)

1. In the following cases, the Operator may change these Terms without the individual consent of Users (Article 548-4 of the Civil Code).
   • When the change conforms to the general interest of Users
   • When the change does not go against the purpose of the contract and is reasonable in light of the necessity of the change, the appropriateness of the changed content, the content of the change, and so on
2. When it makes a change, the Operator will announce on the Service's screen or the homepage that the change will be made, the content after the change and the date on which it takes effect, a reasonable period before that date.
3. If you use the Service after the date on which the change takes effect, you are regarded as having agreed to the changed Terms. If you do not agree, please withdraw (Article 9).

Article 14 (Governing Law and Jurisdiction)

1. These Terms are interpreted in accordance with the laws of Japan.
2. If a dispute arises between the Operator and a User concerning the Service, the parties will first try to resolve it through good-faith discussion.
3. If it cannot be resolved by discussion, the district court having jurisdiction over the Operator's location will be the exclusive agreed court of jurisdiction of first instance.

Article 15 (Miscellaneous)

1. Even if any provision of these Terms becomes invalid, the other provisions remain valid.
2. A User may not transfer their position, rights or obligations under these Terms to another person without the Operator's consent.
3. The Operator may hand over the operation of the Service to a third party (including a corporation, if the Operator is incorporated). If so, it will announce it on the Service's screen or the homepage.
4. Articles 4, 5, 6, 10 and 14 remain valid after withdrawal or the end of use.

Operator Information

When paid plans start, a separate notation based on the Act on Specified Commercial Transactions will be published.