Futoshiki — Inequality Number Logic Puzzle Online

Play Futoshiki free online. Fill the 5×5 grid with 1–5 so every row and column is unique and every < / > sign holds. One logical solution, freshly generated.

#logic #numbers #brain-teaser #single-player

How to play

Tap a cell to cycle 1–5. Each row and column needs 1–5 once, and the open side of every < / > sign must point to the larger number.

About Futoshiki — Inequality Number Logic Puzzle Online

Futoshiki is a pure logic puzzle in the family of Sudoku — but with a clever twist. You fill a 5×5 grid so that every row and every column contains the numbers 1 to 5 exactly once, just like a Latin square. What makes it sing are the inequality signs scattered between cells: each '<' or '>' tells you which of two neighbours is bigger, and your solution must respect every one of them.

Because most puzzles start nearly empty, the inequalities do the heavy lifting. A single '>' at the edge can pin a 5; a chain of '<' signs forces an ascending run; and the no-repeats rule of rows and columns ties everything together. There's no guessing — every step follows logically from what you already know, which makes solving one feel like a small, satisfying proof.

It runs instantly in your browser on phone, tablet or desktop — no download, no sign-up, completely free. Tap a cell to cycle through the numbers, with cells that break a rule flagged in red so slips are easy to catch. Every puzzle is freshly generated with a guaranteed unique, logic-solvable answer, your grid is saved automatically, and the next one is a tap away. A calm, brain-stretching break whenever you want one.

Tips & strategy

  • Hunt for forced extremes. A cell on the small side of a '<' chain of length four must be a 1, and the big end of a long chain must be a 5 — those are free starting digits.
  • Use the row/column rule constantly. Once four numbers are placed in a line, the fifth is forced; combine that with a nearby inequality to settle two cells at once.
  • Read chains of signs together. Three cells joined by '<' '<' must increase across all three, which sharply limits what each can be.
  • A '>' pointing into a cell that already can't be small (because of its row) often locks it immediately — scan for inequalities next to busy rows or columns.
  • Pencil it in your head as ranges. If a cell must be greater than a 3 next door, it can only be 4 or 5; cross-check that against its column.
  • Watch the red outlines. They flag a duplicate or a broken sign the instant it happens, so treat any red cell as a move to rethink before going on.
  • There's never a need to guess. If you're stuck, re-read every inequality touching the emptiest row or column — the next forced move is usually hiding there.

Frequently asked questions

How do I play Futoshiki?

Tap a cell to set its number, cycling 1, 2, 3, 4, 5 and back to empty. Fill the 5×5 grid so each row and column has 1–5 exactly once and every inequality sign between cells is satisfied. Locked given cells can't be changed.

What do the < and > signs mean?

They show which neighbour is larger: the open (wide) side of the sign points to the bigger number. So 2 < 5 and 5 > 2. Vertical signs (∧ and ∨) work the same way between cells stacked above and below.

Does every puzzle have a unique solution?

Yes. Each puzzle is generated and then checked by a solver to confirm it has exactly one solution, reachable by logic alone — you never have to guess.

Why are there so few starting numbers?

That's by design — Futoshiki leans on its inequality clues rather than given digits. The signs, combined with the no-repeats rule, are enough to pin down the whole grid.

Does my puzzle save?

Yes — your grid is stored in your browser after every tap, so you can close the tab and continue the same puzzle later on the same device. The Start button reads 'Continue' when a saved puzzle exists.

Is Futoshiki free and mobile-friendly?

Completely free, with no install or sign-up, and built mobile-first with large tap-to-cycle cells on a grid that fits any screen.