From Nikoli-the Japanese company that invented the game-these puzzles come from the minds of the best Sudoku makers in the world. That´s right: Each one is skillfully crafted by a human, not generated by a computer. So when you put pencil to paper, it´s like you´re going one-on-one with a master. The challenges hit the sweet spot of toughness and elegant solvability and are immensely satisfying to complete. Each week begins with the easiest puzzles and ramps up the difficulty day by day. And just in case you need them, solutions are printed on the backs of the pages. Printed on responsibly sourced paper and 100% recyclable.