This book will challenge seasoned KenKen players, enhance their solving techniques, and provide hours of fun puzzle play and brain training.NEW RULES ARE INTRODUCED ...Each puzzle involves guess work.Every puzzle in this collection is a 6 x 6 puzzle Hours of Fun, Frustration and ultimate Satisfaction KenKen is an exciting, mind-expanding puzzle based on the 'The Art of Teaching without Teaching', an ingenious teaching philosophy developed by KenKen's creator and renowned educator, Tetsuya Miyamoto.