Are you really good at Sudoku? Find out with this challenging collection of 60 medium, hard and very hard Sudoku puzzles from 6 different variants, including Classic, Diagonal, Irregular, OddEven, Chain and Multi. Each puzzle is solved like a regular Sudoku with an additional twist according to the variant rules. There is only one unique solution for each puzzle. Click mouse on the desired square to open dial pad and then click on the desired number. To remove a number, repeat the above using X at the bottom of the dial pad. Numbers can also be placed by pointing mouse on the desired square and then typing with the keyboard.