FreeSudoku

There are lots of Sudoku games available - this is yet another...

Before starting a game, you can set three options:

Training mode allows FreeSudoku to give you hints.
Symmetric games are mirror-symmetrical - this looks pretty, but is otherwise irrelevant
Consistency checking helps prevents silly mistakes, like entering impossible numbers. Some regard this as cheating...

All options are off by default.

There are five difficulty levels. These are based on the complexity of the strategies required to solve the puzzle.

The numbered buttons highlight all existing entries of a particular digit. Click the same digit again to remove the highlighting.

Free Sudoku should automatically start as an applet on the right-hand side of this window. If you prefer, here are two other ways to run the program:

FreeSudoku is a GPL-licensed program whose home is supposed to be http://freesudoku.sourceforge.net/. Unfortunately, the project seems to have been abandoned, so I am posting the source code to my updated version here.