Sudoku Advent Calendar with 200 Sudoku Puzzles Ho Ho Ho! Are you looking for a gift that is both fun and keeps the mind healthy? Sudoku, one of the world’s most popular numbers games is proven by science that boosts logical thinking, helps to improve concentration, develops quick-thinking skills, and reduces anxiety & stress. Research has shown that daily learning, such as playing games like Sudoku, stimulates the brain, improves brain function, and prevents cognitive decline. Unlike standard Sudoku puzzle books, this book contains 6 Sudoku variations to keep your brain engaged.