Sudoku is the puzzle phenomenon from Japan, a game that looks like a math problem, but is in fact a twisting puzzler. The rules are simple: start with a grid consisting of nine threebythree squares in which some of the numbers are already supplied. Fill in the blank squares so that each column, row, and threebythree grid contains a number from 1 to 9 with none repeated. The Sudoku PSP game game features a thousand puzzle problems plus the option to download more later, tutorial and training modes as well as an ingame help, and multiplayer options that include pass play, VS, battle, collaborative play, and even Game Sharing.