Simply Sudoku
a place for your numbers
Simply Sudoku Controls
Using the mouse
Using the keyboard
Changing numbers
Using pencil marks
Extra Features
Using the lock
Going back in time
Settings
Depending on your style of solving, it can sometimes be helpful to mark squares, or to temporarily lock the numbers in a cell. You can do this with the lock feature.

When a square has been locked, a grey lock image will appear in it. You won't be able to make any changes to that square as long as it's locked.

Pick a square in the grid to the right and press the L key to lock it.

 
5
1
4
3
8
7
5
5
2
9
4
1
6
5
7
7
1
5
4
4
3
2
7
5
3
4
8
9
6
2
1
4
8
2