Are you experienced? These are the hardest KenKen for super-solvers only! Acclaimed Japanese mathematics instructor Tetsuya Miyamoto developed KenKen in 2004 with the goal of improving his students' math and logic skills. This understandable, fun and challenging puzzle quickly became a favourite leisure activity for all ages throughout Japan and then for millions of players worldwide. Now it's carried in the New York Times, Los Angeles Times, Chicago Tribune, The Times of London, Scholastic classroom magazines, and more. This book contains 300 puzzles.