Terms of use

Using the site

You may play the puzzles, read the articles, and use the technique guide for your own purposes, including teaching. No account is required and none is offered.

You do not need permission to link to any page here, quote a paragraph with attribution, or print a puzzle for personal or classroom use.

What you may not do

• Republish the articles. Copying a technique guide in full onto another site, with or without credit, is not allowed. Quoting a section with a link back is fine.
• Resell the puzzles or the game. The board, the hint engine and the tutorial are not for redistribution as part of another product.
• Break the leaderboard. It compares players on one device only, so there is little to attack — but automated scripts that fill local storage with fake scores are still a misuse of the site.
• Hammer the server. Scraping at a rate that degrades service for other readers is not allowed. Caching the pages behind a CDN is welcome.

Accuracy

Every board shown in an article comes from a real game, and every explanation is generated by the same engine that runs the hint in the game. The puzzles are checked for a unique solution before they are served.

That said: this is software written by a person, and software has bugs. A puzzle may occasionally be ambiguous, and an explanation may occasionally name the wrong technique. If you hit one, please report it — the contact page is one click away — but do not rely on this site as the sole authority for a competition or a published puzzle.

No warranty

The site is provided as it is. To the extent permitted by law, no warranty is given that it will be available uninterrupted, error-free, or fit for any particular purpose. Nothing here is professional advice: the articles describe solving techniques, not financial, legal or medical matters.

Limitation of liability

To the extent permitted by law, the operator is not liable for indirect or consequential loss arising from use of the site — including lost time, lost data on your own device, or loss caused by relying on an explanation that turned out to be wrong. Your browser's local storage is the only copy of your scores; clearing site data deletes them permanently, and that is not a loss we can compensate.

Nothing in these terms excludes liability that cannot be excluded by law, and nothing removes rights you have as a consumer under the mandatory law of the country you live in.

Advertising and external links

The site carries advertising from third parties and links to external pages, including Google's ad settings. Those services have their own terms and privacy practices, described in the privacy policy. We do not control what an advertiser's landing page does.

Changes

These terms may change as the site changes. The date at the bottom of the page always reflects the current version. Continuing to use the site after a change means you accept the revised terms; if you do not, stop using it.

Contact

Questions about these terms: see the contact page.