Do you like to play Sudoku? If so, you may want to play the USA Today Sudoku Puzzle at puzzles.usatoday.com/Sudoku.

What is Sudoku?

Sudoku is a number placement puzzle invented in Japan, and popularized by the Japanese puzzle company Nikoli in 1996. The game consists of a 9×9 grid partially filled with digits, and the objective of the game is to fill the entire grid with digits so that each column, each row, and each of the 3×3 sub-grids that compose the 9×9 grid are filled with all of the digits from 1 to 9. The game requires logical and deductive thinking, with each filled digit eliminating other candidates in its vicinity, until the game is completed through the process of elimination. A key attraction of the puzzle is that its difficulty is variable, so that there are puzzles suitable for players of all skill levels. The difficulty is both a function of how many squares are filled in at the beginning of the game, and how the filled in squares are arranged, which determines how easily the rest of the digits can be deduced.

There are many advantages to playing the Sudoku game at USA Today (http://puzzles.usatoday.com/sudoku). There is a new puzzle each day, so you always have a new puzzle to begin your day with. Each puzzle is clearly marked with a certain number of stars, which denotes the level of difficulty, so that you are able to play only the games that are just right for you. If you want, you can print out the grid so that you can complete it on paper instead of on the screen. There are, however, several advantages to playing the game on the screen instead of on paper. Firstly, there is a pencil mode, where you can hold down the shift key to make notations in pencil, which appears as a different shade of black so that you know that the entries are tentative. For novice players, there is also a hint mode, where you will be shown the possible entries for that square if you hold down the space bar key. For more advanced players, there is also a conflict eliminator, which automatically catches entries that are illegal. This is a very useful feature which prevents careless mistakes from causing you to be stuck in a dead end. Finally, you can also save and restore puzzles on the website, so that you can complete a puzzle at a leisurely pace.

So, if you are a Sudoku junkie, visit puzzles.usatoday.com/Sudoku, the USA Today Sudoku Puzzle web site for your daily Sudoku fix.