Kakuro is the next hot puzzle craze, and everyone can give it a try with this new, multilevel series. These language-free number puzzles use pure logic and require just simple arithmetic to solve. So, in addition to being fun, they help develop your powers of deduction and reasoning. Beginners can get started - and more experienced solvers hone their skills - with these perfectly tiered belt books, each containing 150 kakuros. They take their cue from the belt colors in martial arts: white is for novices, green for intermediates, brown for very accomplished players, and black for those consummate experts who crave a challenge.