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Overview

Futoshiki

1 player · 5-20 min per session

Fill the grid with digits so each row and column contains each digit once, while satisfying all inequality constraints.

Players: 1P Session length: 5-20 min

PuzzleNumber

Goal & Core Rules

Fill the grid with digits so each row and column contains each digit once, while satisfying all inequality constraints.

Each row and column must contain each digit exactly once (a Latin square).
Some cells may be pre-filled as givens.
Inequality symbols between adjacent cells indicate which side must be larger.
Use the inequalities to eliminate candidates and deduce forced placements.

Classic

Standard grid with inequality constraints.

4x4 Starter

A short 4x4 beginner puzzle for learning the rules.

7x7 Extended

Larger 7x7 normal/hard puzzles for longer deduction chains.

Controls

Mouse

Click a cell to select it
Click the number pad to enter 1-N
Use the clear button or Backspace/Delete to erase the selected cell

Keyboard

Number keys 1-7: enter a value in the selected cell
Backspace/Delete/0: clear the selected cell

Touch

Tap a cell to select it
Tap the bottom/right number pad to enter values
Use pinch zoom plus scrolling when larger 6x6 or 7x7 grids feel cramped

Beginner Tips

Start from strong inequalities: a cell that must be larger than many neighbors has limited options.
Use bounds: if a cell is ‘>’ something, it can’t be 1; if it’s ‘<’ something, it can’t be N.
Combine row/column missing-digit scans with inequality chains.

Advanced Tips

Treat inequality chains as ranges (e.g., A < B < C forces minimum/maximum bounds).
Look for hidden singles created when inequalities eliminate candidates across a unit.
When stuck, revisit the most constrained row/column and re-derive candidate sets.

Origins & History

Futoshiki is a Japanese logic puzzle; it is described as being developed by Tamaki Seto in 2001 and is also known as “More or Less.”

Timeline

2001 Tamaki Seto is credited with developing Futoshiki.

Notable People

Tamaki Seto Credited developer (2001)

Sources

Futoshiki — origin and rules

FAQ

Is Futoshiki the same as Sudoku?

They’re related but different. Futoshiki is a Latin square with inequality constraints, while Sudoku also uses subgrids.

Do all puzzles have a unique solution?

Good puzzles are usually designed to have one solution, but it depends on the publisher.

What grid sizes exist?

This implementation includes 4x4, 5x5, 6x6, and 7x7 puzzles.