Our hardest-yet Sudoku collection, handcrafted by the puzzle masters at Nikoli in Japan. Introducing a book of extra tough, extra thornyand extra addictivepuzzles specially designed for people with Einstein-level Sudoku IQs. Sharpen your pencil. Warm up your gray matter. And pit your wits against the top Japanese puzzle makers in the world. Genius-Level Sudoku features more than 300 brand-new challenges, all rated Good Luck! Nikoli is famous not only for being the first to make Sudoku puzzles, but for being the besteach puzzle is handcrafted, not churned out by a computer program, which makes it uniquely elegant and interactive. The authors are with their solver every step of the way, anticipating the next move and putting up roadblocks.