The rules to Sudoku are very simple: fill in the grid so that every row, every column and every 3x3 box contains the digits 1 trough 9.
There is nothing more to it!
Use the Hint button if you get really stuck. Select the square you need help on and click "Use Hint" to fill in the correct digit. You get up to 3 hints per level.There are 75 levels in total up into the categories of Easy (1-25), Medium (26-50), Hard (51-75). See if you can complete all levels!There is a timer, but no time limit so you can play at your own leisure or put yourself under pressure and challenge your friends.
You can use the keyboard to select squares using the arrow keys and then type in the digit you want to place. 0 will set the squares to empty or you can simply fill the grid by selecting squares with the mouse and pick digits from the small grid that pop up.