Play unlimited Sudoku online from Easy to Evil.
There are different levels that a player can choose which is the beginner, intermediate and advanced. As the level get higher the more challenging the game become.
Completed games are always a type of Latin square with an additional constraint on the contents of individual regions. For example, the same single integer may not appear twice in the same row, column, or any of the nine 3×3 subregions of the 9x9 playing board.