Download or read book Master of Puzzles Sudoku X - 400 Hard to Master Puzzles 9x9 written by James Lee and published by Sudoku X. This book was released on 2019-03-18 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each puzzle consists of a 9x9 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column, diagonal and 3x3 box.