The immensely popular game Sudoku is based on placing nine different signs - usually the numbers 1 to 9 - on a square board with 81 squares. The board has 9 rows, 9 columns and 9 blocks of 3 x 3 squares. Within each group of squares – row, column and block - the 9 different signs must only occur once.

The game only requires the nine different signs to be placed on the board according to simple logic. You need no special qualification and no knowledge of any specific language. Sudoku is for everyone irrespective of nationality, gender, age, religion, occupation or any other characteristic you may think of. So it is a truly international, cross-cultural game. You can play it at home, during travel, on vacation - almost anywhere - except perhaps when your absorption in the game would be inconvenient to your fellow companion!

At the beginning of the game some of the squares hold a number (the given numbers or clues). Your job is to fill the empty squares with numbers, which have not yet been used, so that each row, column and block in the end will hold all the numbers from 1 to 9. Thus each square contributes to or is a part of three groups: a row, a column and a block. In each of the groups the numbers from 1 to 9 should be placed.

A Sudoku puzzle is solved by logic - applying the method of elimination. You rule out all numbers, which cannot be placed in a given square, until only one number is left. That number should then be placed in the square. Guessing would inevitably lead to errors, which may be difficult to correct. The challenge of the game is to assess effectively the possible placement of numbers in the squares.

You can find Sudoku puzzles in newspapers, magazines and books. On the Internet you can also find Sudoku puzzles as well as computer programs, which can design and solve Sudoku puzzles.

A fine sudoku program can be found here.

Sudoku puzzles can be made with any degree of difficulty, so there would be challenging puzzles for anyone to solve, from the beginner to the extremely skilled. The easy puzzles generally have a large number of given numbers or clues (30 or more). The most difficult, which can be extremely difficult to solve, would generally have a lesser number of clues (down to 17).

Sudoku puzzles stimulate your brain and keep you mentally fit as long as you live. So there is every reason for you to go Sudoku!