Ultimate Sudoku


This is a great online version of the classic puzzle as it also notifies you of any errors you make so that the numbers do not repeated. Even with this feature its still a challenge though and its a great brain-stimulating game.

A Soduku grid consists of 81 squares that can be marked with the number between 1 to 9. This grid is also divided into nine 3×3 sub grids.


1 Choice Rule:
Scan for rows columns or sub boxes/grids that already have 8 of the square filled. Hence you can easily fill the remaining square with the only choice available.

Possibility Rule
Often you will come across an empty square with only one possibility. For example if there is a row with two spaces left (example number 2 { 7). But there is an intersecting group (box, now, or column) where one of the numbers are already present (say 7) so the empty space has only one possibility left (2).

There are many more strategies you can find at They really help you better your game and makes the playing more fun (and less frustrating). Learn these techniques and start playing with confidence. Become a Sudoku Master