KENKEN is an arithmetic-based puzzle game that, like sudoku, is played on a grid using numbers.  It goes“beyond sudoku,” however, by taking the puzzle one step further and incorporating math skills, including addition, subtraction, multiplication and division.  Game play ranges from very easy to extremely difficult.  “The hardest ones could challenge even Einstein,” said Robert Fuhrer, the New York businessman whose company, Nextoy™, licenses and markets the puzzle worldwide. iToys’ all-new KENKEN game offers thousands of puzzles on 3x3 to 6x6 grids.KENKEN was launched in 2004 by puzzle master and teacher extraordinaire Tetsuya Miyamoto, quickly becoming Japan’s hottest brain game.  U.S. launch date: February 2009.