How to play Sudoku, at the home of Sudoku on the internet

How to play Sudoku - a beginner's guide

What's it all about?
The goal of Sudoku is to fill all the blank squares in the grid with the correct numbers. In Sudoku Quest, this is done by placing the mouse over a blank square, left-clicking and pressing a number
key 1-9.

How do you know which numbers to place in the empty squares? that's the fun part! Using logic and deduction, you can always work out which numbers go in which squares.

Now for the rules:-
All columns, rows and 3x3 blocks must contain all the numbers 1-9, however they can be in any order, and they do not have to sum up to anything.

Even though Sudoku puzzles use numbers, it has nothing to do with maths at all, you could substitute the numbers for anything, even pretty pictures.

The numbers must be unique
Columns, rows and 3x3 blocks must not contain any duplicate numbers. In Sudoku Quest, these will be shown in red as below. This row has two 8's in it, and therefore is not valid.

Using the pencil
Sudoku Quest allows you to "pencil in" possible values for each square. This can be very useful and may in fact be required for harder puzzles when using more advanced Sudoku solving techniques. To use the pencil in the downloadable version of Sudoku Quest, right-click on a square and press a number key, for the web game, you must hold the space bar and left-click a square.

Is it a real Sudoku?
It is important to note that a "real" Sudoku puzzle has only 1 unique solution which can be reached by logical deduction along. If a Sudoku puzzle can be completed in more than one way, or if you have to guess some of the numbers then it is not a valid puzzle. All of the Sudoku puzzles on this site are valid.

Where to go from here?
Now that you know how to play, why not try: