Each of these 15x15 Sudoku puzzles from best-selling Sudoku author Dr Gareth Moore offers a larger challenge than the regular size grids. Now you must place not only 1 to 9 but also A to F into each of the 15 rows, columns and 5x3 boxes. Despite their size, all of the puzzles are carefully designed to be fun rather than frustrating, and attractive symmetries make them pleasing to the eye as well as the brain. Each puzzle has a guaranteed logical solution which does not require lots of pencilmarks to be made, and they're all printed on high-quality large paper with each puzzle over 7 inches wide, so no staring at lots of tiny numbers is required