Start your day out on the right foot with a brain puzzle! The Sudoku Desk Calendar features puzzles of varying levels of difficulty that will challenge any player on almost every day of the year. How challenging each puzzle can be is ranked out of 4 stars and included on each page along with a month at a glance view. What more could a Sudoku solver want than a puzzle a day? Difficulty varies, with indicators displayed out of four at the top of every page.