Goal
The goal is to fill in all the empty cells on the board with the correct numbers.
Rules
Cells each take a number between 1 and 9. A number may only appear once in a single row, column or three-by-three box.
How to Play
Click a cell to select it. Then click a number in the button bar to set or clear the number for the selected cell.
To take notes, click the small numbers inside a cell when it is selected. Alternatively, click the notes button in the lower right corner, and then click the numbers in the button bar.
Keyboard Shortcuts
Press the arrow keys to move the cursor around. Press a number key from 1 through 9 to set a number. Press backspace to clear a number. Press N to switch to note-taking mode, or press Shift-1 through Shift-9 to
set notes without switching modes.
How to Play
Tap a cell to select it. Then tap a number in the button bar to set or clear the number for the selected cell.
To take notes, tap the notes button in the lower right corner, and then tap the numbers in the button bar.