Sudoku World is a great free online Sudoku game and it is perfect for training. Looking at the rules of Sudoku, you are supposed to insert the numbers 1 to 9 in any of the 3x3 grids without repeating a number. You must also do this without repeating the numbers in the columns and rows of the larger 9X9 grid. This is very easy for a Sudoku aficionado to know, but for the newbie, this can be a challenge. This particular game has three modes, namely, Easy, Medium and Hard, so you can select the one you want depending on how good you are. Once you get into the game, you will see a timer which will be counting the second that you are taking to complete the puzzle. However, the point to note is the fact that the game is great for training. When you put a number into a square that is the wrong one, it will be highlighted in red and you will not get ay score. This will make you examine why it cannot be the right number. When you put in the right number, it will be highlighted in green and you will earn 10 points. This is a game that can teach someone how to approach Sudoku; through playing and trying to understand why the number was highlighted in red will show you how to play the game. Once you begin making a score, you will be penalized with one point for every wrong choice that you make. This is great to avoid guesswork and encourage the player to think before entering a number. Once again; this is a great game for training someone to become a good Sudoku player. You have to play this game to experience how lovely it is and also how challenging it can be. You really do not want to lose those points.