Black Belt KenKen
![Black Belt KenKen](/image/97/81/45/49/04/20/5/9781454904205.webp)
Acclaimed Japanese mathematics instructor Tetsuya Miyamoto developed KenKen in 2004 and it has since taken over the puzzling world. It takes a page from karate, another Japanese art, as each title is graded by colour: White for easy, Green for med...