XSudoky is a program written in C to play and to learn the methodologies of logical resolution of sudoku noticing and highlighting them; you would learn and understand the methods like: Intersection, Naked, Hidden, X-Wing, Sword-Fish, Jelly-Fish, Squirm-Bag, XY-Wing ...

Different puzzles are inside already to play, but you can download other puzzles copying from magazines or from the web utilizing a simple text editor and using a format that sweetable for your use.

XSudoky is FREE and OPEN SOURCE, you can  compile it very easily or you can take the RPM which is already filled up. The binary program is very reduced to be fast and not invasive or used on old computers or 'puppy' versions.

XSudoky required Linux and X11 (with Windows you should use Cygwin) and it's translated in Italian, French, English.