When Your Hard Sudoku Becoming Too Hard?

Sudoku puzzles became the most common puzzles in all the magazine paper that published since 2005. The simplicity of the game and the fact that it is based on digits made the game international and ageless almost overnight.

Creating a Sudoku puzzle is an art that takes into consideration the beauty of the board its symmetry and the balance between the different squares, lines and columns. Every board has to have a solution and only one solution. You can find 2500 examples for such puzzles in the site www.SudokuToPrint.com.

The Sudoku designer must see the solution course and to verify the player enjoy solving the puzzle. By making the solution a little bit tricky but not too hard this task can be achieved.

There are Sudoku puzzles that fill all constrain above however they are too hard for human being player.

 In the Sudoku community it is already known that there are Sudoku boards with only 17 hints, which still have a unique solution. When somebody tries to solve such a board he will probably need to guess ten cells until the board can be solved in the standard methods. It means that if the guess is between only two possibilities (and most of the cases are far more possibilities) the solver will need to try 2 in power of 10 that's equals to 1024 trials. So the Sudoku creator has to take this into his consideration and to write a Sudoku that is hard enough but not too hard for the average player.

 The rule of thumb is to take maximum two or three cells that need to be guessed. Researches showed that the board can cause frustration and the player will leave the board unsolved. In the site www.SudokuToPrint.com each puzzle has its own score number except the regular score; Easy, Hard, Advanced etc. Furthermore in the very hard book the score formula includes the number of the cells that the player has to guess.

 For example:

Score                                 Level                            No. guessed cells

354                                    Easy                             0

784                                    Advanced                     0

10201                                Hard                             1

31022                                Very Hard                     3

The formula contains G (G for guess) parameter as the number of guess multiply by 10,000 plus the other ingredient of the score.                     

 Advanced_score=10,000G + Standard_score

The multiplying by 10,000 comes to separate the "standard score" from the greatest dominator for the difficulty level. The exact score of the Sudoku is very important, when the Sudoku player sees this "warning" he able to know what kind of puzzle he is going to deal with, is it light Sunday morning Sudoku or heavy Sudoku for sleepless night.

My last tip to the beginner Sudoku author is to solve each board he creates in order to verify that the board has a solution and that it is fun solving it. After solving the puzzle by hand you can see that your formula to difficult level is accurate and even improve it according to the experience you get from the solving process.