### Draw/Play help

- Click a cell, and use the keypad to enter numbers.
- Use the spacebar or delete to remove a number.
- Hold down the <Ctrl>
or <Alt> key to add multiple
numbers to a square as pencil marks.
Pressing <Ctrl> or <Alt> and the number again removes the
pencil mark.
- Move the current (highlighted) cell with the arrow keys.
- Click the buttons on the right hand side to perform actions:
- Today - start from today's
puzzle.
- Revert - revert to the starting
clues (only applicable for Daily Sudoku puzzles).
- Reset all - remove all numbers from
the grid.
- Fix/Unfix - fixed numbers (black) cannot be removed or
overwritten, while unfixed numbers
(blue) can.
- Sweep - show all possible numbers
for each cell, overwriting your current pencil marks.
- Clean - remove all pencil marks.
- Grade - update the puzzle
difficulty based on the numbers given. Too
hard means the solver doesn't know how to solve the
puzzle.
- Hint - get a logical next step
(highlighted in red).
- Solve - solve the puzzle.
- Ascii - get a text version of the
puzzle. This is particularly useful to email a puzzle to a friend,
or paste into the discussion pages.
- Save - Save your progress. You can
store only one puzzle, so this function overwrites any previous
save. (The Save option does not currently save pencil marks, but we're
working on it!)
- Load - Load your saved puzzle.
- Print - create a printable page
with the selected parameters. (Note: requires Acrobat Reader).

- The auto check option highlights
obvious mistakes; for example, two 1's in the same row. Note that
this (intentionally) does *not* verify that the number is correct,
only that it is not illegal with respect to the current state of the
grid illegal.
- Select auto advance to have the
highlighted cell advance on number entry.
- Select auto sweep to automatically
update the options in each cell as you input numbers.
- The title box allows you to name the
puzzle for the printable page. Note that this isn't the way to
retrieve puzzles from the archive.

### Requirements