The Original Sudoku Desk Calendar: Sudoku for Sudoku lovers—a year of all-new, full-color puzzles from Nikoli, the Japanese company that invented the craze. Not just the original, these are the best Sudoku: Each puzzle is handcrafted, not computer generated, so it's like challenging a master, move by move. The calendar eases you in every Sunday, with the puzzles increasing in difficulty over the course of the week. EAN: 9780761174226 ISBN: 0761174222