Fill in the empty squares with numbers 1 through 9. You can't put the same number more than once in any one row, column, or 3x3 box.

When the puzzle is successfully completed there will be no empty squares and each number will appear once in every row, column, and 3x3 box.

Features:
- Standard 9x9 SuDoku grid.
- Enter and play your own or published puzzles.
- Over a million preset puzzles.
- Authentic SuDoku puzzles - they have only one solution and can be solved by logic alone.
- Non-digit symbols. Optionally play with letters, maths symbols, or boxes instead of digits.
- Enhanced statistics. Statistics for min, max, average, and total solution playing time per level added.
- Optional digit cross-hatching and other solving aids.
- Hint function. Shows the square the software would complete next. Shows invalid squares.
- Optional manual and semi-automatic pencil marks. Entering blank in a blank square fills in the pencil marks for that square.
- Optional automatic pencil marks.
- Game level display.
- Optional dotted pencil marks. The Japanese typically place dots on their newspapers to represent pencil marks.
- Stats of current game and overall playing history.
- General preferences settings for show game timer, auto off timeouts, etc.
- Display preferences to select monochrome, large fonts, etc.
- Sudoku is a registered mark of Nikoli (www.nikoli.co.jp) within Japan.

Update Description:
- Tough game category.
- User puzzle solution.
- One-handed navigation.