Sudoku is a very simple puzzle and full of fun. It’s very easy to learn as it has only three simple rules. But it is very difficult to solve a Sudoku puzzle for a beginner using the rules. Once a person is able to solve his/her first Sudoku and solves out some more, then he/she becomes addicted to it. I personally feel myself addicted to Sudoku.

I had first seen a Sudoku puzzle in a newspaper and found it quite interesting.  Whenever I am at home and have free time, I always try out the Sudoku in the daily newspaper. I have also installed a Sudoku puzzle game in my mobile. It helps to pas time whenever I am alone and have nothing else to do.

Sudoku requires no mathematical calculations; what it requires is just some simple logical thinking. Let me explain what Sudoku is and how to solve it.

Sudoku puzzle consists of a 9×9 square i.e. a total of 81 squares. These squares are subdivided into 9 small 3×3 squares. That is, each sub-square consists of 9 squares. Now, there are three very simple rules to fill up the squares:

1. Each row must contain all the nos. from 1 to 9.
2. Each column must contain all the nos. from 1 to 9.
3. Each 3×3 subsection must contain all the nos. from 1 to 9.

Each Sudoku puzzle consists of some already filled up squares. With the help of these filled up squares, you have to deduce logically the number for other squares. The difficulty level of certain Sudoku depends upon the number of already filled up squares. If there are more filled up squares, then the Sudoku is of easy level. And if the number of filled up squares is less, then the Sudoku is of difficult or moderate level.

For every Sudoku, there is only one unique solution. There are two ways by which a Sudoku can be solved out:

1. Start scanning a specific row or column or a specific subsection for a specific no. See where a specific number can fit in a row. If you cannot find out a unique position in that row, then move to the next row. Likewise, do the same thing with respect to column and subsections. You can do this by keeping in mind the fact that in a row, column or subsection, no number can be repeated. I solve out Sudoku using this method.
2. Pencil in all the cells with the possibilities. If there are some cells with only one possibility, then fill them up with pen. Now, start with one of the cells with 2 possibilities (3 possibilities if 2’s is not available). Write with pencil one of the possibilities and then fill up the rest squares with respect to that. If you haven’t chosen the correct possibility, then you will find a conflict after 3 or 4 numbers are penciled in. If a conflict is found, then erase them and start again and fill up the other left out possibility with pen.

The first Sudoku championship was held in Lucca, Italy on March 10-12,2006, Jana Tylova of Czech Republic as the winner.