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 .

About Matrix Sudoku

  Matrix Sudoku is a popular puzzle consisting of a grid of 9 by 9 numbers. Each grid number is in the range 1-9 which can only occur once in any row/column combination and the 3x3 square in which it resides. ('Sudoku' is a Japanese word that meaning "the numbers must be single", or "the numbers must occur only once". )The goal of Sudoku is to fill all the blank squares in the grid with the correct numbers.

  Matrix Sudoku also support the variant sudoku: Nonomino Sudoku, also known as geometric Sudoku. This variation most closely approximates regular Sudoku, but instead of nine 3x3 groups, it has nine groups in irregular nonomino shapes.

Screenshot

Playing Regular Sudoku
Regular Sudoku		 Playing Nonomino Sudoku
Nonomino Sudoku