Once you have grasped the basic Sudoku rules and used the Sudoku strategy tips and tricks detailed in my previous easy tutorial posts you’ll see how easy it is to become quite familiar with the basic concept of Sudoku puzzles.
The previous posts shows you how to solve Sudoku using simple strategies and techniques. But as you become more adept at solving Sudoku, you’ll no doubt want to learn about more advanced Sudoku tips and strategies.

As explained in my previous posts, using pencil marks or notations to make a note of possible candidates is a great Sudoku trick to help you solve Sudoku puzzles by listing the values that could go into a particular cell.
But, these notations can also be used to apply many advanced techniques. By spotting patterns in your notations you can apply certain advanced Sudoku strategies. Whenever you solve a square, you must remove that number from the pencil marks in all other squares in the same row, column and block.

One example of an advanced Sudoku strategy is the X Wing.

The X Wing is in effect, an advanced method that uses the fact that in certain scenarios, there can only be 2 possible ways of inserting two numbers in a given set of four squares, which are the corner cells of a rectangle. Because this indicates a relationship between diagonally opposite corners it forms an ‘x’.

To illustrate this, here are 2 diagrams showing the X Wing strategy, with 2 variations – column and row X Wing.

sudoku xwing row variation

sudoku xwing column variation

There are many more advanced Sudoku strategy tricks and I will be introducing them over in the next few posts, before going into detail with a tutorial of each Sudoku strategy.

.