Sudoku is considered to be a very effective educational game popular worldwide. People play this game both offline and online. The board game displays a 9x9 grid in which the gamer is required to fill the appropriate numbers. The large grid is further divided into small boxes with certain grids. The game can be played all alone or in multiplayer mode. The main objective in the game is to place the numbers from 1-9 in each of the grids. Even the larger grid should not have any number repeating itself in the entire line. I must say that this game is a brain twisting online game that is great fun to play nevertheless.