You solve a Sudoku puzzle by filling in numbers (1-9) in a 9×9 square.
- Rule 1: every row should contain ALL 9 numbers, and no number can occur more than once.
- Rule 2: every column should contain ALL 9 numbers, and no number can occur more than once.
- Rule 3: every 3×3 square should contain ALL 9 numbers, and no number can occur more than once.
(see also sudoku.com)
My Helper just checks the 3 rules above and will indicate which cells can easily be filled in because there is only 1 option left. Yes, it can be kind of a spoiler, so only use it to get out of a deadlock, or if you’re in a hurry, or to show off.
The more difficult puzzles will require you to cunningly plot your strategy 2 or 3 steps ahead, which my Helper page will not do or help you with. If you want to spoil even these brain gymnastics, check Sudoku Solver by Logic
For those of you who like a client program that can work off-line, check Sudoku Solver (Windows – free).