Sander Alsema, has made a Soduko Tool. This program is written in machine-code and is available for the Commodore C64. What makes this Soduko solver special is that is can solve the Soduko's from the Dutch newspaper NRC-handelsblad. With the cursor and 1 to 9 keys you can fill in the known numbers. With F1 you can find one number, or you can solve the complete Sudoku in one go with the "crack" function.