Hidden Rule

About Hidden Rule

Hidden Rule plays like the classic 2, 4, 6 task from psychology. Each day opens with three numbers that follow the hidden rule, such as 36, 412 and 949. You type any number from 1 to 999 and press Test, and the game answers YES or NO. Rules use divisibility, digits or size, sometimes joined by AND or OR.

Fewer tests score better, and each puzzle has a par, a target rather than a limit. A list of your tests can be filtered and sorted to spot the pattern, and a hint is available at the cost of marking your result. The game's own advice is to test a number that could prove your theory wrong.

When you stop testing, the second stage begins: a set of numbers to mark as fitting the rule or not, with one submission. Each day is numbered, there is an archive of earlier puzzles, stats and a streak, and a practice puzzle teaches the game. It suits players who like logic puzzles about patterns rather than grids.

How to play Hidden Rule

1. Look at the numbers that already follow the day's rule.
2. Type a number from 1 to 999 and press Test to see whether it fits.
3. Keep testing to narrow the rule down, ideally within par.
4. Press Prove your rule and mark each number in the final set YES or NO in one submission.

Screenshots

Tips

• Test numbers that would break your current theory, not ones that confirm it.
• Check digit rules and divisibility separately: try a number with the same digits in another order.
• Use the filter to view only YES or only NO results when the list grows.

Questions