Independently Published 1000 Sudoku Puzzle Books Hard Extreme: Brain Games for Adults - Logic Games For Adults

This book contains 1000 sudoku puzzle books hard, very hard & Extreme. All of the puzzles inside the book are 9x9 in hard to extreme level.Sudoku rules are easy. Each number 1,2,3,4,5,6,7,8 and 9 must appear only once in each row, column, and region