True Sudoku–Truly one solution

What is Sudoku? The aim of this game is to fill 1 to 9 into each grid cell so that each number can only appear once in each row, each column and each mini-grid/block. Why another Sudoku game? We all know that there are many Sudoku games in the market. But did you know that most games though labelled Sudoku are not really Sudoku.