Sudoku Genius (Paperback Book)
... are The levels are Daunting, Tortuous, Merciless, Harrowing, Horrific, Maddening, Murderous, Devastating, and Deadly.
starts out with a brief definition of the basic concepts and methods used to solve ... so erasing over and over should not be a problem.
is a challenge to even the most seasoned Sudokuist. By the end
of this book
, you'll be a Sudoku Genius.