John's Sudoku

John's Sudoku is one of the most comprehensive Sudoku game systems. It can randomly create puzzles for six difficulty levels. You may never encounter the same puzzle. But you can do the same puzzle by defining user-defined puzzles. Or you can define your own puzzles through Sudoku books. You can also share the same puzzle with friends through the import/export function of this system. The following is a summary of the functions:
1. Randomly create puzzles for six difficulty levels.
2. Users can define their own puzzles, such as from Sudoku books.
3. Check the status and highlight errors.
4. Use the most advanced highlighting function to easily view the working cells.
5. Automatically mark the selected cells.
6. Undo/Redo function.
7. Automatically mark (or erase) all cells with one key.
8. Return to the previous correct state by 'eliminating incorrect entries'.
9. Puzzle-solving function.
10. Share the fun with friends by inputting/outputting puzzles.
11. Reset to the original puzzle.
12. The game is automatically saved and you just need to click "Restore".
1. Randomly generate puzzles for six difficulty levels.
2. Users can define their own puzzles, such as from Sudoku books.
3. Check the status and highlight errors.
4. Use the most advanced highlighting function to easily view the working cells.
5. Automatically mark the selected cells.
6. Undo/Redo function.
7. Automatically mark (or erase) all cells with one key.
8. Can return to the previous correct state by 'eliminating incorrect entries'.
9. Puzzle-solving function.
10. Share the fun with friends by inputting/outputting puzzles.
11. Reset to the original puzzle.
12. The game is automatically saved and you just need to click "Restore".