What Is Futoshiki? The \"Greater Than Sudoku\" Explained

If you've heard a puzzle called "greater than sudoku" and wondered what it actually is, the answer is Futoshiki — a logic puzzle that looks like a small sudoku sprinkled with greater-than and less-than signs. It keeps sudoku's core idea (fill a grid so no number repeats in a row or column) and adds one twist: little arrows between some cells tell you which neighbor is larger. That single addition changes the whole feel of the puzzle, and it's why Futoshiki has picked up a handful of descriptive nicknames. This explainer breaks down exactly what Futoshiki is, how it works, and why it's called the greater than sudoku.

Want to try one while you read? Open a Futoshiki puzzle in another tab.

The short definition

Futoshiki is a number-placement puzzle played on an N×N grid (commonly 4×4 or 5×5). You fill it so that every row and every column contains the digits 1 to N exactly once — the same Latin square rule that powers sudoku. The twist is a set of inequality signs (< and >) printed between some pairs of neighboring cells. Every one of those signs must be satisfied: the open side always faces the larger number.

So a finished Futoshiki obeys two things at once: no repeats in any line, and every arrow pointing correctly from the bigger value to the smaller one.

Why it's called "greater than sudoku"

The nickname is the most literal description possible. Sudoku is the familiar part — a grid you fill without repeating digits in a line. The "greater than" part refers to the inequality signs that make Futoshiki unique. Put them together and you get "greater than sudoku," which is exactly how a lot of newcomers first encounter the puzzle.

It's worth knowing that, unlike sudoku, Futoshiki has no 3×3 boxes — only rows, columns, and the arrows. That makes the grid simpler in one way (fewer regions to track) and richer in another (the arrows do a lot of work).

What the symbols mean

The signs are easy once you see the trick: the wide, open mouth always faces the bigger number, and the point faces the smaller one.

• 3 > 1 — three is greater than one.
• 2 < 5 — two is less than five.

That's the entire symbol system. Some sites also display the constraints as ∧ and ∨ when the cells are stacked vertically, but they mean the same thing — which way is "bigger." The full symbol reference lives on the Futoshiki rules page.

How you actually solve it

Because the arrows give you relationships rather than fixed digits, solving Futoshiki is about squeezing certainty out of those relationships. A cell that must be greater than a neighbor can't be the smallest value; a run of arrows forces the digits to climb in order. Combine those facts with the no-repeat rule and the grid resolves itself — no math, no guessing. For a full walkthrough, see how to solve Futoshiki, and for the key move, inequality chains.

The puzzle's many names

Futoshiki travels under several names, all describing the same inequality puzzle:

• Futoshiki — the original Japanese name (from 不等式, meaning "inequality").
• Greater Than Sudoku — the most popular English nickname, for obvious reasons.
• Inequality Puzzle — a direct, descriptive translation.
• Unequal — used by some puzzle sites.
• More or Less — another descriptive alias you'll occasionally see.

They all point to the same grid-and-arrows logic puzzle. We dig into where the name comes from in the history of Futoshiki.

Is it like sudoku?

Yes and no. The Latin square skeleton is identical, and any sudoku player will feel at home — but the arrows replace the 3×3 box constraint and change how you think, giving you order-based clues instead of placement-based ones. We compare them head to head in Futoshiki vs Sudoku.

Try it for yourself

Now that the idea makes sense, the best next step is to solve one. Start with an easy 4×4 Futoshiki to get a feel for the arrows, or read the step-by-step beginner guide first. It takes about five minutes to learn and a lifetime to stop enjoying.

Frequently asked questions

What is Futoshiki?

Futoshiki is a logic puzzle played on an N×N grid where you place the digits 1 to N so that none repeats in any row or column, and so that every inequality sign between cells is satisfied. It's like sudoku without the 3×3 boxes, plus greater-than and less-than constraints.

Why is Futoshiki called "greater than sudoku"?

Because it combines sudoku's no-repeat grid with greater-than and less-than signs between cells. The "sudoku" part is the familiar Latin square; the "greater than" part is the inequality constraint that makes Futoshiki distinct. The nickname is simply a plain description of how it plays.

What do the < and > symbols mean in Futoshiki?

The open, wider side of the sign faces the larger number and the point faces the smaller one. So 3 > 1 means three is greater than one, and 2 < 5 means two is less than five. Every such sign in the grid must be true in the finished solution.

Is Futoshiki the same as the inequality puzzle?

Yes. "Inequality puzzle" is a direct descriptive name for Futoshiki, since the arrows are inequality constraints. It also goes by "unequal," "more or less," and "greater than sudoku" — all the same grid-and-arrows puzzle.

What does Futoshiki mean?

Futoshiki comes from the Japanese word 不等式 (futōshiki), meaning "inequality." The name reflects the puzzle's defining feature: the greater-than and less-than relationships between cells.