The given Sudoku board had 81 cells. The cells can be divided into
Nine Rows of 9 cells each.
Nine columns of 9 cells each.
Nine square boxes (3 x 3 boxes) of 9 cells each.
The puzzle is solved by filling the numbers 1 to 9 in all of the rows, columns and square boxes. No number will be repeated within a row, column or a square box.
Some of the cells are pre-filled with numbers which cannot be changed. The sudoku puzzle has only one solution.
You can select a sudoku puzzle from the three difficulty levels Easy, Medium and Hard as seen in the navigation bar. The current level selected is highlighted. You can select a level based on your sudoku solving skill.
Error Alert - When an incorrect number is entered in a cell you are alerted of the same by the cell color changing to red. You can disable this feature by unchecking the 'Error Alert' checkbox. This feature is enabled by default.
Highlight - When a number within a cell is selected all the cells in the sudoku board with the same number are highlighted by changing color to light green. You can disable this feature by unchecking the 'Highlight' checkbox. This feaure is enabled by default.
Timer - You can see the time elapsed while solving the sudoku puzzle. The timer is not displayed by default. You can control the timer display using the 'Show Timer' checkbox.
Pause Game - You can pause the timer for the current sudoku puzzle by clicking the pause button.
Enter hints - By clicking the 'Enter hints' button you should be able to enter multiple numbers or hints in cells. You have to exit the hints mode by clicking the button again for resuming to solve the sudoku puzzle.