Terms of Service

The Service is operated by:

Stuart Donald BellRichard-Sorge-Str. 1110249 BerlinGermany

Email: contact@sudokumountain.com

Further details are set out in our Imprint.

Sudoku Mountain is a website offering Sudoku puzzles to play in the browser, printable Sudoku PDFs to download, and articles about how to solve them. Use of the Service is free of charge. We reserve the right to add paid features in the future; if we do, the present free features remain available unless we tell you otherwise.

We do not guarantee that the Service will be available without interruption or free from errors. We may modify, suspend, or discontinue features at any time, including for maintenance or technical reasons.

You may use most of the Service without an account. To save your puzzle history and statistics across devices, you can create an account by entering your email address; we then send you a one-time sign-in link ("magic link"). No password is set or stored. You may optionally provide a first name during sign-up so we can address you by name in the streak banner.

By creating an account you confirm that:

• you are at least 16 years old, or you have your parent or guardian's consent;
• the email address you provide is yours and is accurate;
• you will not share your sign-in link with others, since anyone with the link can sign in to your account;
• you are responsible for keeping your email account secure.

You can delete your account at any time at /en/account/delete — sign in, type the confirmation word, and your account, puzzle history, and streaks are removed immediately. The action is irreversible. We may close an account that materially breaches these Terms; where reasonable, we will give notice first.

When using the Service, you agree not to:

• use automated means (scrapers, bots, headless browsers, scripts) to access the Service at a scale that disrupts other users or imposes a disproportionate load on our infrastructure;
• attempt to gain unauthorised access to any part of the Service, other users' accounts, or our infrastructure;
• reverse-engineer, decompile, or otherwise attempt to extract the source code of the Service except where applicable law expressly permits this;
• circumvent, disable, or interfere with security or technical-protection features of the Service;
• use the Service for unlawful purposes, or to transmit content that is unlawful, infringing, or misleading;
• copy, redistribute, or republish content from the Service in a way that exceeds private, non-commercial use, except as permitted by Section 5.

All content on the Service — including the puzzle generator, the editorial articles, the printable PDFs, the layout, the logo, and the Sudoku Mountain brand — is owned by the operator or its licensors and protected by copyright, trade-mark, and related rights.

You may print, save, and use puzzles and printable PDFs for your own private and non-commercial use, including in classrooms by individual teachers. You may not redistribute the printable PDFs in bulk, sell them, or use them as part of a competing product. If you would like to use our content commercially, contact us — most reasonable requests can be agreed.

The Sudoku puzzle as a logical structure is in the public domain; nothing in these Terms restricts your right to play, share, or write about Sudoku in general.

We provide the Service with reasonable care, but to the extent permitted by law we make no warranty that the Service will meet your requirements, be error-free, secure, or available without interruption. Any decisions you make based on content on the Service — including health-adjacent claims about the cognitive benefits of puzzle-solving — remain your own.

We are liable without limitation for damages caused by intent or gross negligence, for injury to life, body, or health, and under the German Product Liability Act.

For damages caused by ordinary negligence, we are liable only for breach of an essential contractual obligation (a "cardinal duty" — an obligation whose fulfilment makes the proper performance of the contract possible in the first place and on whose observance you may regularly rely). In such cases liability is limited to typical and foreseeable damages.

Any further liability is excluded.

This limitation does not affect your statutory consumer rights.

We may amend these Terms when our Service changes, when the law changes, or to clarify existing terms. The current version is always available on this page. If a change is material, we will make it visible on the site before it takes effect. If you do not agree with the change, you may stop using the Service or delete your account.

These Terms apply for as long as you use the Service. You may stop using the Service or delete your account at any time. We may stop offering the Service to you in the cases described in Section 3.

These Terms and your use of the Service are governed by the laws of the Federal Republic of Germany, excluding the UN Convention on Contracts for the International Sale of Goods.

If you are a consumer, mandatory consumer-protection rules of your country of habitual residence apply in addition to and prevail over German law where they are more favourable to you.

If a provision of these Terms is or becomes invalid, the remaining provisions stay in effect. The invalid provision is to be replaced by a valid provision that comes closest in legal and commercial effect.

If you have questions about these Terms, write to us at contact@sudokumountain.com.