Overview

Futoshiki

후토시키

Place numbers without repeats in rows/columns—and obey every inequality sign.

Like Sudoku, but with inequalities that instantly narrow candidates. Small signs, big deductions.

Players: 1P Session length: 5-20 min

Logic PuzzleNumber Puzzle

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.

Controls

Mouse

Click a cell/element to select
Use the input UI (numbers/marks/lines) to apply
Right click/secondary action: mark or erase (if supported)

Keyboard

Number keys: enter value (if supported)
Backspace/Delete: clear (if supported)
Arrow keys/Tab: move focus (if supported)

Touch

Tap: select/enter
Long-press: mark/secondary action (if supported)
Use the on-screen pad/buttons to input

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?

Common sizes include 5×5 and 6×6, but larger sizes are possible.