(If you’ve never played before, it’s very straightforward – please see below)

If you’ve never played before, it’s very straightforward. All you have to do is enter the numbers 1-9 into the 9×9 grid above, so that each of the horizontal and vertical lines, and each of the 3×3 smaller grids, contain all of the digits 1-9. There’s no guesswork involved, and no maths – you solve the puzzle using logic only.

There are five levels of difficulty, from very easy to fiendish. This page comes up with a random level – if you’d like to try a different level just click on the “New Puzzle” drop-down menu under the board.

When you’ve finished, just click the “Check Sudoku” button and you’ll be told whether you’ve got it right or not – any wrongly-placed numbers show up as red squares. (Be warned, though – the red squares only show up duplicate numbers, so there’s no point in simply entering a number into a square and hitting the “Check” button to see if it’s right!)

If you’d like more information on how to solve Sudoku puzzles, just click on the “How to solve it” link at the top right hand corner of the board.

Why not give it a go? Have fun!