Sudoku Puzzle game

Sudoku Puzzle game is very popular currently. People can play it On-Line, or using small digital game boxes or on paper forms. Obviously, the most convenient way is that draw a 9*9 table on a piece of paper, and write down several fixed numbers in the table, then fill other blanks. But when I fill it, I need to erase the wrong numbers. It turns into a mass after several wrong guess. So I designed a new way to play Sudoku Puzzle game by using a plastic board just like checker board, and the individual numbers would be the chessmen. How to mark the right numbers and the guess numbers which you are not very sure? The answer would be using different color: one side of the number chessman is green, the other side is yellow, and everyone knows that green light in traffic means OK - safe. Play Sudoku game by this way, people neither need computer and Internet nor pencil and eraser. Checker board and chessmen would never out of power like batteries, and it is cheap!