数独解法ツール
Sudoku solver
UPDATE (August 2010): A few visitors pointed out that the old software I was using here wasn't always able to solve some of the more difficult problems. Thanks to Bill DuPree, this solver tool now has a new engine that appears to have no problem solving minimal sudoku problems with just 17 cells filled. Just one caveat: unlike the previous solver, this one will not attempt to solve any puzzles with fewer than 17 filled cells.
If you have any problems using this tool, please let me know.
To use this tool, fill in the table with the numbers from a sudoku puzzle, leaving the other spaces blank. Then click the Solve button. If you like, you can give it a test drive with this sample puzzle.