- HoDoKu is a sudoku helper written in Java and available in English and German. Generate sudokus in five different and fully configurable difficulty levels. Solve them yourself (with help from HoDoKu's hint system) or let HoDoKu do it for you.
- Free • Open Source
The project seems to be no longer updated, but last version, 2.2.0, released in July 2012, it's fully working and can be still downloaded from the official website.