Futoshiki FAQ

Futoshiki is a logic puzzle played on a square grid. You fill every cell with a digit from 1 to N so that no digit repeats in any row or column, and every inequality sign (< or >) between two neighbouring cells is true. Some cells start filled in. The name is Japanese for "inequality".

Yes. futoshiki.app is completely free with no download, no account and no ads between puzzles. Everything runs in your browser, on desktop and mobile.

Boards run from 4×4 to 9×9 in two difficulties. Easy keeps plenty of givens and signs. Hard removes clues until the puzzle is close to minimal, so you need chains, pairs and elimination rather than simple single-cell deductions.

Futoshiki is the Japanese word for "inequality" (不等式). The puzzle was published in Japan in the early 2000s and later spread to newspapers and puzzle sites around the world, where it is also sometimes called Unequal.

Select an empty cell and enter a digit. Each row and column must contain 1 to N exactly once, and each sign must point to the smaller number: a < between two cells means the left one is smaller, a > means it is larger, and vertical signs work the same way. Use the givens and the signs to narrow down each cell until only one digit is possible.

Yes. Each puzzle is generated from a random Latin square and then checked by a solver that confirms exactly one solution remains before it is shown to you. You never need to guess — there is always a logical next step.

Tap or click a cell and then a digit on the number pad, or use the keyboard: arrow keys move, 1 to 9 enter a digit, Backspace or 0 clears. P toggles pencil notes, U undoes, H gives a hint, N starts a new puzzle and M toggles sound.

Turn Notes on and the number pad toggles small candidate digits in the selected cell instead of placing a real digit. When you place a real digit, it is automatically removed from the notes of every other cell in that row and column, so your candidates stay accurate.

Red marks a rule violation among the digits you have entered: a repeated digit in a row or column, or an inequality sign that is not satisfied. The board checks rules rather than the answer key, so a digit can look fine and still be wrong; a hint will always give the correct digit.

A hint fills one cell with its correct digit — the selected cell if it is empty or wrong, otherwise a random unsolved one. Hints are counted on screen, and a puzzle solved with hints is still a win but does not set a best time.

The sign points to the smaller number. In "2 < 4" the point faces the 2. Horizontal signs compare a cell with the one to its right; vertical signs compare a cell with the one below it, with ∧ meaning the upper cell is smaller and ∨ meaning it is larger.

Start with the extremes: the largest digit cannot be on the small side of a sign and 1 cannot be on the big side. Follow chains of signs, use givens to bound their neighbours, look for a digit that fits in only one cell of a row or column, and use pairs of cells with identical candidates. Pencil notes make each of these easier.

They are close relatives. Both require each digit once per row and column, and both are solved by elimination. Futoshiki has no boxes; instead the inequality signs provide the extra constraints, which makes chains and bounds the key techniques.

The clock starts on your first entry and stops when the puzzle is solved. Best times are kept separately for every board size and difficulty, and only solves without hints count.

Yes, on your device. Your unfinished puzzle, best times, streaks, board size, difficulty and sound setting are stored in your browser and restored when you come back. Nothing is uploaded and there is no account. Clearing your browser data resets it.

Yes. The board resizes to fit the screen and the number pad and tools sit directly beneath it, so 4×4 to 6×6 puzzles are comfortable one-handed. Larger boards work too, though the cells and notes are smaller.

It has short synthesized sound effects for placing digits, notes, errors, hints and solving a puzzle. Press M or use the speaker button to mute; the setting is remembered on your device.

Gameplay runs entirely in your browser. We use Google Analytics for aggregate traffic and a few gameplay events such as starting or solving a puzzle. Your progress is stored only in your own browser storage. See the privacy policy for details.