Su Doku, "the crosswords without words," come with a warning: it is seriously addictive. One doesn't need to be a mathematical genius to solve these puzzles; it is simply a question of logic and a little patience. Here is a collection of 100 new puzzles arranged according to difficulty.

Grand Master Su Doku Book 1 2005, HarperCollins Publishers

ISBN-13: 9780060893286

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