Shows various highlight modes, with candidates in the blank cells.
You can leave this open while you play, and use it to enter numbers, pencil marks, as well as showing and hiding candidates and more.
If you don't like the default colours, you change change every one of them! There are separate sets of colours for playing, designing and printing etc.
There is also a wide range of other settings which can be configured.
Don't worry if you don't know much about the game.
The help feature describes every feature, and various techniques for solving the game.
Print Your Own Sudoku Games
You can print games to play without your computer.
This was printed on a laser printer.