Sudoku Keyboard Operation

Here's a page from the extensive help system for SudokuDragon. It is displayed as a help screen when running the program. To get the full picture Download our Sudoku Dragon and see the screen in its full context.

Our menu and toolbar page lists all the Sudoku playing commands that are available from the program menu and toolbar. All the most frequently available actions are also available at the touch of a button - from the keyboard.

Selecting a square

To select the Sudoku grid press TAB until one of the cells shows a flashing underline. You can also select a square by clicking the mouse on a square.

Moving around the grid

The arrow keys (up, down, left and right) move by one Sudoku square in the corresponding direction. These only operate when a grid square is already selected.

The page keys (Page up, Page down) move by one region up or down. If you use the control (CTRL) key at the same time it will move horizontally by a region rather than vertically.

Home takes you to the top left square and End takes you to the bottom right.

Setting the contents of a square

To set the value for a Sudoku square you must first select it - using selection and navigation and then just use the appropriate key '1' to '9'. If you have Number lock (Num Lock) enabled you can assign a value with the number pad keys. [Note: you can use the mouse wheel as an alternative way of allocating a value to a square].

Clearing the contents of a square

Use the Delete key or Space to set the currently selected square as unallocated.

Setting Tentative Possibilities and Impossiblities

For the more difficult puzzles, many Sudoku puzzlers will want to mark possibilities on squares. You can do this simply and easily by selecting an unallocating and then pressing down control (CTRL) key at the same time select the appropriate key '1' to '9' for the possibility you want to set. The possibilities are shown as small numbers (or letters) at the bottom of the square. If the possibility is already set this will set it as impossible (reverse colours). Using the same key combination again will clear it. To clear all the tentative possibilities for a square press Delete. You can set all tentative possibilities to be the same as the automatic possibilities by pressing F8 or Edit | Set Auto Possibilities. The setting of tentative possibilities is remembered so the program can selectively Undo and Redo them if you find you need to change your mind later.

Showing Possibility Analysis

The possibility bar lets you quickly get the computer to show what is possible to assign and where. You can use it by clicking on the symbols in the toolbar or by using ALT key with a number '1' to '9' to select a possibility option. If the possibility is already chosen this will clear the possibility display. To switch on all possibilities use the F4 function key. A highlight option is provided that quickly shows the number of squares remaining.

Keyboard Commands

Key	Command
F1	Display help information
F4	Show/hide computed possibilities for all values 1..9
F7	Clear all tentative possibilities in current square
F8	Set tentative possibilities to match automatic possibilities for the current square
F9	Give a hint to help solve the puzzle
F10	Show the current status of the game
F11	Show possibility analysis for the current square
F12	Auto Allocate an 'easy' to solve square
CTRL+Z	Undo the previous square allocation
ALT+Back	Undo the previous square allocation
CTRL+SHIFT+A	Redo the previously undone square allocation
CTRL+SHIFT+N	Generate a new puzzle
CTRL+SHIFT+O	Open an existing puzzle file
CTRL+SHIFT+P	Print the current puzzle
CTRL+SHIFT+S	Save the current puzzle
CTRL+1..9	Set or clear tentative possibility/impossibilty for 1..9 (if using numbers)
CTRL+A..T	Set or clear tentative possibility/impossibilty for A..T (if using letters)
ALT+1..9	Show/hide computed possibilities for 1..9
Pause	Temporarily pause the game timer