Independently Published 1000 Very Hard Sudoku Challenge: Brain Games for Adults - Logic Games For Adults

This book contains 1000 puzzles sudoku book for adults very hard and extreme level. All of the puzzles inside the book are 9x9 grid. 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. Comp