How to play

How to play Futoshiki: rules and interactive tutorial

Futoshiki combines two simple ideas: every row and column must contain each number once, and inequality signs between cells add extra constraints. This guide shows you how to read those signs and use them effectively before choosing a puzzle from the Futoshiki library.

What is Futoshiki?

Futoshiki is a logic puzzle played on a square grid. Every row and column must contain the numbers 1 to N exactly once. Inequality signs between some neighbouring cells add extra constraints.

Goal of the game

Fill every cell with a number from 1 to N, without repeating a number in any row or column, while satisfying every inequality sign.

Rules

Rule 1

Use the numbers 1 to N for the size of the grid: 1–4 on a 4×4, 1–6 on a 6×6, and so on.

Rule 2

Each number appears once in every row.

Rule 3

Each number appears once in every column.

Rule 4

Respect every inequality between neighbouring cells: the pointed end always faces the smaller number.

Every DIGIGMA puzzle has a logical solution. You do not need to guess.

How to read the inequality signs

The signs sit between two cells. Horizontally you will see < or >; vertically, ∧ or ∨. In every case, the pointed end faces the cell that must contain the smaller number.

2 is less than 4
2<4

In 2 < 4, the point of < faces 2, the smaller number.

A vertical inequality
2∧5

With ∧, the point faces upward, so the top cell must be smaller than the bottom cell. ∨ works in the opposite direction.

When you’re stuck

  • Look for cells next to especially restrictive inequalities, particularly around the extreme values 1 and N.
  • Check rows and columns that are missing only a few numbers.
  • Update candidates after every new placement.
  • Avoid guessing: DIGIGMA puzzles are designed to progress by deduction.

In Practice mode, Hint can point you towards a useful next step and Reveal completes the grid. These aids are not available in Ranked.

Common mistakes

  • Reading an inequality backwards: the point always faces the smaller number.
  • Repeating a number in a row or column.
  • Forgetting the vertical ∧ and ∨ inequalities.
  • Guessing when a constraint can still eliminate candidates.

Practical tips

  • Start with inequalities involving the smallest or largest possible values.
  • If a cell still has two or three candidates, note them in Draft and compare them with its row and column.
  • Once these habits feel natural, choose a puzzle from the Futoshiki library.

Interactive tutorial

The tutorial below teaches you how to use inequality signs with the same keypad as a real game. Afterwards, open the Futoshiki library and try a full puzzle.

FAQ

Which way does the inequality point?
The pointed end always faces the smaller number, whether the sign is horizontal (<, >) or vertical (∧, ∨).
Do I need to guess?
No. Every DIGIGMA grid is designed to be solved by deduction.
What sizes are there?
Grids come in 4×4, 5×5 and 6×6. The keypad shows only the numbers relevant to the chosen size.
What is Draft?
Draft marks are the candidates that are still possible in a cell. They are simply a memory aid while you solve.
What should I do when I get stuck?
Return to the tightest inequalities, update your candidates, and inspect rows or columns that are nearly complete.

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