KenKen can be described simply as sudoku with basic math (addition, subtraction and/or multiplication and division). It's a fun, addictive, clever puzzle that's winning fans the world over. Already more than one million KenKen books have been sold in Japan and is a huge hit in The Times of London. Now, America can catch KenKen fever! Our first book contains 100 easy addition and subtraction KenKen puzzles with "How to Solve" instructions and an introduction by puzzlemaster Will Shortz. Tetsuya Miyamoto , the creator of KenKen, is a math teacher. He developed KenKen to help his student develop their calculation and logic skills. He runs a unique mathematics class for grade school children in Japan where he practices “The Art of Teaching Without Teaching.” His teaching method and use of KenKen in his classroom have proven extremely successful. His students regularly go on to be accepted at the most prestigious schools in Tokyo. KenKen was developed in 2004 by acclaimed Japanese mathematics instructor Tetsuya Miyamoto. His goal was to improve his students' math and logic skill, so he developed a puzzle that would be understandable, fun, and challenging for any level of student. Most importantly, he wanted the puzzle to encourage independent thinking, emphasizing trial and error, concentration, and perseverance. His methods and puzzle were immediately successful. It quickly became a favorite leisure activity for all ages throughout Japan and then for millions of players worldwide. In 2008, KenKen came to the United States. Soon, it was the first daily feature since the crossword puzzle to appear in The New York Times . Whether in the classroom, on the beach, waiting for a bus, standing atop a mountain―anywhere you might be―KenKen is always stimulating your brain. It's the puzzle that makes you smarter! Will Shortz has been the crossword puzzle editor of The New York Times since 1993. He is also the puzzlemaster on NPR’s Weekend Edition Sunday and is founder and director of the annual American Crossword Puzzle Tournament. He has edited countless books of crossword puzzles, Sudoku, KenKen, and all manner of brain-busters.