Sudoku tips

General

• Start with the easy puzzles, and then move on to the harder ones.
• Make small pencilmarks noting which numbers are allowed in the empty squares. This will help narrow down possibilities later on.
• Always double check before placing a number.
• Never guess! Only make moves based on logical deductions.

Note: There is only one unique solution for each puzzle.

When solving on paper

• Use a soft erasable pencil and a high quality eraser.

When playing on a computer

• Use Preferences options in toolbar for a better personal playing experience.
• For faster solving, numbers can be placed by pointing mouse on the desired square and then typing with the keyboard.
• Use pencilmarks to note which numbers are allowed in the empty squares. This will help narrow down possibilities later on.
• When using the Highlight selected number option, selected numbers may be changed using the spacebar, arrow keys, or by clicking the number in the grid.
• Same applies when using the Highlight excluded squares option.