Features

GNOME Sudoku provides a number of features that help you play puzzles.

Nòtas

Notes or Pencilmarks let you take notes in each square. Many players use notes to track possible values for squares.

Hints and Auto-Fill

You can use hints and auto-fill to have GNOME Sudoku tell you about possible values for a square or automatically fill in a square for you.

Enlusiment

In highlighting mode, the current row, column and box are highlighted in different colors to make scanning the board easier.

Trackers

Trackers make trial-and-error solutions easier to keep track of. When you track a set of moves, the numbers are entered in a special color to help you distinguish those moves from moves made earlier in the game.

5.1. Taking Notes

To write notes (also known as “pencilmarks”) in a square, first select the square with the keyboard or mouse. Then, do one of the following:

  • Click in the upper region of the square (the region is highlighted with a square when you move the mouse over a selected square).
  • Type N

This will bring up a field in which you can type your notes. Type Return when you are finished editing your note.

You can also take notes in the bottom of the square by clicking in the bottom of the square or by typing M. However, this area is used when you ask for a hint, so you should not use this area for your own notes if you also plan to use hints.

You can clear the notes at the top of the square by typing Alt-N and at the bottom of the square by typing Alt-M.

You can add a number to the notes at the top of the square by typing Ctrl-1 through Ctrl-9 and remove a number from the notes by typing Alt-1 through Alt-9.

5.2. Hints and Auto-Fill

The Hint and Fill features work based on the logical possibilities given the current board. They do not work by looking at the solution. If you have made an error in an earlier move, these features may fill in or suggest incorrect values.

5.2.1. Hints

GNOME Sudoku can give you hints based on your current board. You can ask for a hint for the currently selected square by clicking hint, selecting Tools ▸ Hint, or typing Control-H. This will put a list of possible values in the bottom of the square.

Figure 4Hints

If you want to remove or alter the hint, you can edit the text by clicking in the bottom of the square.

For very difficult puzzles, you can choose to have Sudoku show you the possible values for all squares. To turn this mode on, toggle Tools ▸ Always show hint. Note that this can make easy puzzles too easy, so you should use this mode sparingly.

Figure 5Sudoku in Always-Show-Hint Mode

5.2.2. Fill Square

To automatically fill in a square for which there is only one possible value, you can click Fill, select Tools ▸ Fill, or type Control-F. This is useful, for example, when you have filled in 8 or 9 squares in a row and want to quickly fill in the last empty square.

If there are more than one valid value for the entry, nothing will happen.

5.2.3. Fill All Squares

You can automatically fill in all squares for which there is logically only one value at the moment. To do so, select Tools ▸ Fill all squares, or type Control-A.

This feature should only be used to help you when you are very stuck on a difficult game. Using this feature on an easy game can solve the entire puzzle in one click, resulting in a very boring game!

5.3. Enlusiment

You can turn on highlighting to automatically highlight the current row, column and box in different colors. This can make it easier to see which values cannot go into a current square. To toggle highlighting, you can:

  • Click Highlighter
  • Visualizacion ▸ Highlighter
Figure 6Sudoku with highlighting

5.4. Trackers

You can use trackers to keep track of multiple moves at a time. Tracked moves will be entered in a different color to make them visually distinct. You can also delete all tracked moves at one time. This is particularly useful for solving difficult puzzles by trial-and-error.

Some sudoku players believe you should never use trial-and-error to solve a puzzle. These players should not use this feature.

You can toggle the tracker-interface by doing one of the following:

  • Espleches ▸ Track additions
  • Click Track additions

This will bring up a list of trackers on to the right of the current game. Create a new tracker by clicking Add Tracker. From this point forward, any number you enter will be part of the selected tracker.

You can clear all the values that are part of a tracker by selecting the tracker from the list and clicking Clear Tracker. You can clear all values that are not part of a tracker by clicking Clear Others.