This is a book of 400 Giant 12 x 12 Sudoku puzzles. These puzzles work in exactly the same way as traditional Sudoku puzzles, but a little bit bigger to offer a little bit more challenge. Each row, column and region must contain the numbers 1-9, but they must also contain one each of the letters A, B and C. You can still use exactly the same techniques to solve these puzzles, but they will take you a little longer There are 400 puzzles altogether, split up as follows. 100 Easy puzzles. Ideal to get started. 100 Medium puzzles. For you to move on to once you start feeling more confident. 100 Hard puzzles. Getting harder 100 Tough puzzles. For the diehard Sudoku fans. Something for everyone "