How to Play
What is Sudoku (9x9 board)
The word Sudoku means "single number in an alloted place" in Japanese.
These are the basic rules. Every sudoku Sudoku si a square of 81 cells divided into 9 columns and nine rows and in 9 subsquares (3x3) of nine cells each.
Solving takes usually from 10 to 30 minutes, depending on puzzle level, your skill and experience.
Some cells are filled with a number at the beginnning: the remaining are to be filled by the player using numbers from 1 to 9, without repeating a number twice on each column, row or subsuquare (each of them must contain only one 1, one 2, one 3, and so one).
The game requires logic and patience.
The numerals in Sudoku puzzles are used for convenience (for example in 16x16 board we use letters): arithmetic relationships between numbers are irrelevant.
This program supports also 16x16 games with numbers from 1 to 16 and 256 cells with 16 cols, rows and subsquares! (if normal sudoku are not enaugh for you).
Mathematics related to sudoku
More information @ http://en.wikipedia.org/wiki/Sudoku
Program use
To place a number in a cell: select it on the toolbar and then click on a blank box.
hover with the mouse over a cell end push the number on the keyboard.
You can select a number to write down also by clicking on a given number.
You can also place pencilmarks by clicking Right Mouse Button, when you are unsure about the number to be written, or at the moment the cell could contain multiple numbers (and you can not choose then).
Basic Strategy
Fill in the grid so that every row,every column, and every 3x3 box contains the digits 1 through 9.
Referring to the image, the highlighted cell must contain 7 because:
There must be one 7 in the cell's 3x3 box
The top/left cell and the center/left cell can not contain it because in their column there is already a 7 (upwards)
The center/center, center/right, center/bottom, bottom,right cells can not contain 7 because their rows are already containing that number.
Ours is the only avaible cell, so it contains a 7.
Another strategy: When a cell has a many numbers filled in its rows, columns, or 3x3 boxes, you can count the numbers that can not be placed in our cell and place the only one (or more by pencilmarking with RMB) that can be placed.
More information @ http://en.wikipedia.org/wiki/Sudoku
Francesco Rossi
