Logic Puzzle FAQs

A puzzle you solve by deduction rather than by knowledge or guesswork. You are given a set of facts — clues, numbers along the edge of a grid, a row of shapes — and exactly one arrangement fits all of them. Nothing depends on trivia or vocabulary, which is why logic puzzles travel across languages and ages so well.

Read everything before you write anything, then work in passes rather than in order. Mark what a clue rules OUT as carefully as what it rules in, because eliminations are what actually narrow a grid. After every new mark, re-read the clues you have already used — a clue that told you nothing an hour ago often becomes decisive once one more square is settled.

Something where progress is visible. Word search asks only that you look carefully, and a nonogram rewards you with a picture as it comes out. After that, futoshiki is the gentlest true grid puzzle here: small, and every deduction is a comparison you can say out loud.

Far longer at first than it will later, and that is normal. Published averages for a sudoku-sized grid run about five to fifteen minutes on easy and thirty minutes or more on hard, but experience matters more than difficulty — the same grid can take a beginner half an hour and a regular solver three minutes. Speed is a side effect of practice, not the point of it.

In a properly made one, never. If you find yourself guessing, either the puzzle has more than one solution — which means it was built badly — or there is a deduction still on the board that you have not spotted. Every grid puzzle on this site is checked by a solver that uses no guessing at all, and is only published if that solver can finish it unaided.

It should, and that is the difference between a puzzle and a pastime. A grid with two valid answers cannot be reasoned to an end, so somewhere you would have to pick one. Every puzzle here is counted by a second, independent search before it ships, and anything with more than one answer is thrown away rather than published.

Yes, and most puzzles you meet online already are. The usual method is to build a complete valid solution first and then remove clues while the puzzle stays uniquely solvable. That is exactly how the puzzles here are made — the answer exists before the puzzle does, which is why none of them can turn out to be impossible.

Yes, all of them, with no paywall and no limit on how many you play. There are no adverts and no trackers either, which is unusual enough to be worth stating plainly rather than burying in a privacy policy.

No. There is no sign-up, no email, and nothing to install. Your progress and any best scores are kept in your own browser, so they never reach a server — and clearing your browser data clears them.

They are good for attention, patience and systematic thinking, and most people find them genuinely calming — the small, steady progress is the appeal. What they reliably improve is your ability to do that kind of puzzle. Treat the broader claims with some caution; see the next question.

There is no good evidence that they do, and it is worth being straight about it. Puzzle-solving is associated with better cognitive ageing, but association is not prevention, and specialists in the field are clear that doing puzzles has not been shown to stop cognitive decline. Play them because they are enjoyable and absorbing. That is a good enough reason.

They are one of the most accessible there is: no equipment, no opponent, no time pressure, and you can stop mid-puzzle and come back. That is partly why this site has no timer anywhere, uses large tap targets, and keeps its text at a size that does not need squinting at.

A picture logic puzzle, also sold as Hanjie, Griddlers or Paint by Numbers. Numbers along each row and column tell you the runs of shaded squares in that line — a clue of "4 8 3" means a block of four, then eight, then three, in that order, with at least one blank between them. Shade the right squares and a picture appears.

Reasoning about shapes and patterns rather than words or numbers — sometimes called abstract reasoning. A question shows you figures that follow a hidden rule and asks what comes next, which is the odd one out, or what a shape looks like folded or reflected. Because there is no language in it, it is one of the few puzzle formats that works the same for everyone.

The name belongs to a specific puzzle: a 1996 problem by the philosopher George Boolos, involving three gods called True, False and Random who answer only in a language whose words for yes and no you do not know. You get three yes-or-no questions to work out which is which. It is a famous one-off rather than a puzzle type you can practise.