Millions of different possible puzzles
 Three difficulty levels from easy to hard.
 Check correctness as you go along
 Hints available when you get stuck
 Print out the puzzle so you can play your sudoku on pager.
 Variants:Nonomino Sudoku, also known as geometric Sudoku also included .

How to play

  There is really only one rule to Sudoku: Fill in the game board so that the numbers 1 through 9 occur exactly once in each row, column, and 3x3 box. The numbers can appear in any order and diagonals are not considered. Your initial game board will consist of several numbers that are already placed. Those numbers cannot be changed. Your goal is to fill in the empty squares following the simple rule above.

  In Matrix Sudoku, to add a number to the grid, you must first select the number, and then click to place the tile on the grid square you have chosen. You can also clear (cancel) the number you have placed by selecting the space and placing it to the grid square. You can use the "hint" (only 3 times) to disclose the number on the chosen square.

  How do you know which numbers to place in the empty squares? That's the fun part! Using logic and deduction, you can always work out which numbers go in which squares. Refrence here to learn how to solve Sudoku Puzzles.