Sudoku.php is a Web-based program that tries to
implement the same rules a human would use to
solve a Sudoku puzzle. It can solve many Sudoku
puzzles, but not all because it only uses logic
and refrains from brute-force solving. You can
interactively influence the solution process to
try out rules of your own. You can easily enter a
Sudoku puzzle and save it for repeated use.