What is Greater Than Sudoku?
Greater Than Sudoku is normal sudoku with extra signs printed between some of the squares. The board is the same 9×9 you already know, with the same nine 3×3 boxes, the same rows and the same columns. The fresh twist is the little arrows: wherever you see a sign, the two squares on either side of it have to obey it. The one on the open side is bigger; the one the point aims at is smaller.
You can play Greater Than Sudoku as soon as you’re comfortable with our classic 9×9 sudoku. The number rules are exactly the same: each row, each column and each 3×3 box still has to contain the digits 1–9 with no repeats. The signs just add one more rule on top of the puzzle you already know.
Puzzle books sometimes call this game "inequality sudoku", "comparison sudoku" or "Futoshiki sudoku" — Futoshiki is a Japanese puzzle built from the same greater-than idea. Whatever the name, the signs work the same way they do in a maths lesson: 7 > 2 and 2 < 7.
How is it different from regular sudoku?
In a normal sudoku you have three rules: every row, every column and every 3×3 box must contain the digits 1–9 with no repeats. Greater Than Sudoku keeps all three of those and adds one more — every sign printed between two squares has to be true once both squares are filled in.
Signs only ever join two squares that are right next to each other, side by side or one above the other. A left-right sign looks like > or <. An up-down sign looks like ∧ or ∨, which is the same shape rotated a quarter turn: the point still aims at the smaller number.
- 🟪 Every row, column and 3×3 box must contain 1–9 (same as classic sudoku)
- ▶️ Where a sign is printed, the square on the open side is the bigger one
- ◀️ The pointy end always aims at the smaller number
- 🔼 Up-and-down signs (∧ and ∨) follow exactly the same rule
- ⬜ Squares with no sign between them have no extra rule — they are ordinary sudoku squares
The 4 simple rules
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One of each in every row
Every row needs the digits 1 through 9 — no repeats.
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One of each in every column
Every column needs the digits 1 through 9 — no repeats.
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One of each in every 3×3 box
Each of the nine 3×3 boxes needs the digits 1 through 9 — no repeats.
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Every sign must be true
Look at the two squares a sign sits between. The number on the open side has to be bigger than the number the point aims at. Always.
The chain trick that unlocks the puzzle
The single most useful habit in Greater Than Sudoku is looking for chains. A chain is three or more squares linked by signs that all point the same way, like a staircase: a < b < c.
Chains squeeze the numbers hard. In a < b < c, the first square can never be 8 or 9, because two bigger numbers still have to fit above it. The last square can never be 1 or 2, because two smaller numbers have to fit below it. The longer the chain, the tighter the squeeze.
The two ends of a chain are the best places to start any puzzle. A four-square chain has an end that can only be 1, 2, 3, 4, 5 or 6 — and once you combine that with the row, column and box, there is often only one number left standing.
Our Auto Notes button works all of this out for you. It fills in pencil marks using the row, the column, the 3×3 box, the signs against squares you have already filled AND the chain squeeze — so your notes are never wrong.
How to play on Sudoku for Kids
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Tap an empty square
It turns yellow. The signs attached to it light up too, so you can see straight away which neighbours it has to beat — or lose to.
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Tap a number
Use the number pad under the board, or just type a number on a keyboard. Tap the same number again to take it back out.
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Use ✏️ Notes for maybes
Notes mode writes small numbers in the corner of a square so you can keep track of the possibilities without committing.
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Let 🔢 Auto Notes do the maths
One tap fills every empty square with the numbers that are still legal — signs and chains included.
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Tap ✅ Check any time
It tells you how many numbers need fixing, without telling you which ones. Broken signs also turn both squares pink the moment they clash.
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Stuck? Tap 💡 Hint
A hint fills in one correct square for you. It counts in your stats, but there is no penalty — hints are there to be used.
Easy strategies for kids
- 🐊 Read every sign as a crocodile — the mouth opens at the bigger number
- ⛓️ Find chains of signs pointing the same way and work from the ends inwards
- 9️⃣ A square with a sign opening towards a bigger neighbour can never be 9
- 1️⃣ A square with a sign pointing at a smaller neighbour can never be 1
- ✏️ Turn on Auto Notes early — it applies the sign rules for you
- 🔁 After every number you write, re-read the signs around it
Most kids pick up Greater Than Sudoku in about five puzzles. If you have never played sudoku of any kind, a couple of rounds at Easy 9×9 sudoku first will get the basic pattern into your head. Once rows, columns and boxes feel automatic, the signs are a fun new layer on top. If pencil marks are new to you, our guide to how pencil marks work is a good five-minute read.
Why kids love Greater Than Sudoku
- 🧮 Real maths practice hiding inside a puzzle — comparing numbers, over and over
- 🐊 The crocodile trick sticks; kids who play this stop mixing up > and < in class
- 🕵️ Detective brain — every sign is a clue about a square you cannot see yet
- ⏱️ Quick wins on Easy, proper challenges on Expert
- 📱 Plays great on phones, tablets, Chromebooks and laptops
For parents and teachers
Greater Than Sudoku is an unusually good fit for the classroom because it rehearses one specific skill — comparing two numbers and choosing the right symbol — hundreds of times inside a puzzle a child actually wants to finish. Children who confuse > and < on a worksheet usually stop confusing them after a few games, because here the symbol has a consequence.
Every puzzle on this page is generated with exactly one solution and is checked by computer before it reaches the screen, so a child can never get stuck through no fault of their own. There is no timer pressure, no fail state and no advertising in the middle of the board. Mistakes are counted quietly and never punished.
Easy suits roughly ages 8–9, Medium ages 9–10, Hard ages 10–11, and Expert is a real challenge for confident solvers of any age. A good classroom pattern is one Easy puzzle as a warm-up, then a shared Medium puzzle on the whiteboard with children explaining which sign they used.
Ready for more?
Once Easy Greater Than Sudoku feels comfortable, try Medium Greater Than Sudoku. From there you can graduate to Hard Greater Than Sudoku, and finally take on Expert Greater Than Sudoku — our toughest inequality puzzle.
Want a similar brain workout? Our Thermo Sudoku is the closest cousin — instead of single signs it draws whole thermometers that numbers must climb. Our Skyscraper Sudoku hides the comparison at the edge of the grid instead. Or try Hyper Sudoku, X-Sudoku, Killer Sudoku and Jigsaw Sudoku for four completely different twists. Younger players can start with our 4×4 sudoku and 6×6 sudoku starter grids.
Frequently asked questions
What age is Greater Than Sudoku good for?
Most kids enjoy Greater Than Sudoku from about 8 years old, once they are comfortable with regular sudoku and know that > means "bigger than". Younger kids should start with our 4×4 or 6×6 starter grids, then classic 9×9, and add the signs when rows, columns and boxes feel automatic.
Which way round do the > and < signs go?
The open side always faces the bigger number and the point always aims at the smaller one. Lots of children remember it as a hungry crocodile whose mouth opens towards the bigger meal. Up-and-down signs (∧ and ∨) work in exactly the same way.
Is Greater Than Sudoku harder than normal sudoku?
Not really. The signs add one extra rule, but they also hand you extra clues, and a puzzle with plenty of signs can often be solved faster than a plain grid with the same number of starting digits. Most kids find our Easy level about as hard as Easy classic sudoku.
Does every pair of squares have a sign?
No. Only some neighbouring pairs show a sign — Easy puzzles show the most and Expert the fewest. Squares with no sign between them are ordinary sudoku squares with no extra rule.
What is Futoshiki, and is this the same game?
Futoshiki is a Japanese puzzle built entirely from greater-than signs on a small grid, with no 3×3 boxes. Greater Than Sudoku takes that idea and lays it over a full sudoku grid, so you get both sets of rules at once.
Do the puzzles always have one answer?
Yes. Every puzzle is checked by computer before it appears, and only puzzles with exactly one possible solution are used. You never have to guess.
Can I play without making an account?
Yes! Every game on this site is free, with no signup, no email, and no ads in the way of the puzzle.
Does it save my progress?
Yes — your puzzle, notes and timer save automatically in your browser. Close the tab and come back later, it will still be there.
Try other sudoku games
Different rules, same friendly board. Pick a sibling puzzle to play next.