"KenKen was developed in 2004 by acclaimed Japanese math educator Tetsuya Miyamoto. His educational philosophy is: ""The Art of Teaching Without Teaching."" KenKen is a fun and addictive puzzle for people of all ages. It improves logical deduction skills while using fundamental mathematics -- addition, subtraction, multiplication and division. KenKen actively stimulates the min... https://www.kenkenpuzzle.com/