Confident solvers who think they€ve got Sudoku down cold will have to think again, because these are absolutely the most fiendishly difficult, devilishly baffling Sudokus ever devised…and the biggest, too. Created by hand in Japan-from Nikoli, the company responsible for the puzzles€ popularity in that country-the collection includes megasudokus on a 25 x 25 grid, designed to give even the sharpest minds a workout. True to its title, it€s the ultimate challenge, and one that millions of Sudoku-obsessed fans will find irresistible. And for total newcomers brave enough to high-dive in at the deep end, there€s a quick tutorial to get them started.
