Futoshiki
A Latin square with greater-than clues — deduce every number.
How to play Futoshiki
Futoshiki (Japanese for "not equal") is a logic puzzle on an N×N grid. Like the rows and columns of Sudoku, each row and column must contain the numbers 1 to N exactly once, with no repeats. The twist is the inequality signs between some cells: wherever you see a <, >, ∧ or ∨, the two numbers it sits between must obey it — the sign always points at the smaller number.
Tap a cell, then tap a number to place it. From the given numbers and the inequalities alone, the whole grid can be worked out by logic.
Solving tips
- Chains of inequalities are gold. If three cells in a line read a < b < c, then in a 5×5 the smallest of them is at most 3, and a run of four forces the ends toward 1 and the maximum.
- The extremes. A cell that must be greater than several neighbours is pushed toward the top of the range; one that must be smaller is pushed toward 1.
- Cross with the Latin rule. Once a number is placed, it's banned from the rest of its row and column — combine that with the signs to pin down the next cell.
- Pencil the possibilities. For a tight cell, jot the values that survive both the inequalities and the row/column rule, then eliminate.
Why Futoshiki is satisfying
Futoshiki is pure deduction with a very small rule set, so it's quick to learn but surprisingly deep. Because the only clues are a handful of givens and the greater-than signs, every step is a genuine logical inference — there's no arithmetic to grind through, just clean "if this, then that" reasoning. It's a lovely palate-cleanser between the heavier number puzzles.
Frequently asked questions
Is Futoshiki free here?
Yes, completely free with no sign-up. It runs in your browser and your best time is saved on your device.
What do the signs mean?
Each sign points to the smaller of the two numbers it sits between. So "3 < 5" is fine because the open side faces the larger number; a vertical ∧ means the cell above is smaller than the one below.
Do rows and columns work like Sudoku?
Yes — each row and each column must contain every number from 1 to the grid size exactly once. There are no 3×3 boxes in Futoshiki.
Does every puzzle have one solution?
Yes. Each board is generated and verified to have exactly one solution, reachable by logic alone.