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🔥 27–30 given numbers

Hard Printable Sudoku

100 free hard puzzles for experienced solvers who enjoy pencil marks and pattern spotting.

Hard puzzles require at least one advanced pattern: hidden pairs, naked or hidden triples, X-Wing or XY-Wing.

All hard puzzles

Puzzle guide

About hard Sudoku

What they are

Hard Sudoku drops to 27 to 30 givens and guarantees that you will need an advanced pattern before the grid gives in. Each puzzle here calls for at least one hidden pair, a triple, an X-Wing or an XY-Wing, techniques that rely on full pencil marks rather than scanning alone.

How to play

Start with a full candidate pass: note every possible digit in every empty square. Clear the easy singles first, then look at how candidates line up. An X-Wing appears when one digit has exactly two spots in each of two rows, and those spots share the same two columns.

Tips

Use a sharp pencil and an eraser, and update your notes each time you place a digit. Hunt for triples in crowded boxes. If nothing moves, pick a single digit and trace every place it can still go across the whole board.

Who they suit

These grids are aimed at experienced adult solvers, teenagers who have outgrown medium puzzles, and anyone learning named strategies. They make a good weekend puzzle or a quiet evening challenge.

Printing

Print hard puzzles one per page so the squares are big enough for small candidate numbers. The solution sheet sits on its own page for checking at the end.

Good to know

Hard Sudoku questions

When a digit can appear in exactly two squares in each of two rows, and those squares line up in the same two columns, the digit must sit at two opposite corners. It can then be removed from every other square in those columns.

No. Each hard grid has exactly one solution and can be reached with logic. Our solver checks that before a puzzle is published.

Between 27 and 30, with the rest of the 81 squares left for you to work out.

Need a break from the numbers?

Try a hard riddle

Sudoku and riddles train the same muscle: spotting what must be true. Here are a few hard riddles with answers.

hardMiddle school
🤔

Two fathers and two sons share three cookies so everyone gets one. How is that possible?

Type:Math
Reveal answer

The answer is

They are a grandfather, a father and a son

Hints and details
hardMiddle school
🤔

How can you add five to nine and get two?

Type:Math
Reveal answer

The answer is

On a clock: 9 o’clock plus 5 hours is 2 o’clock

Hints and details
hardMiddle school
🤔

Forward I am heavy, but backward I am not. What am I?

Type:Wordplay
Reveal answer

The answer is

The word “ton”

Hints and details
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