If you are an expert at Sudoku but want an extra challenge then you will love our Extreme Sudoku Puzzles.
Featuring 156 Sudoku Puzzles of 3 difficulties: Hard, Very Hard and Extreme
Features:
Buy on Amazon US
Buy on Amazon UK
*If you live in a different country that has an Amazon Marketplace you can find our book by typing this code into the Amazon Search Bar : B08FS476TH