Su Doku: Grandmaster. Book 2

Take cover! This second book in the Grandmaster series contains even more of the most ferocious puzzles ever to stalk to earth, puzzles so hard they have never been set down in print before. Compiled by Andrew Stuart, a top British puzzle maker, this collection of Su Doku will test the best. Every puzzle can be solved through logical deduction alone. But they go well beyond the level of the most difficult daily puzzles and will challenge your solving abilities to breaking point.