Su Doku: Grandmaster. Book 1

Brace yourself! This book contains some of the most difficult So Doku puzzles ever created on 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 of daily puzzles and will challenge your solving abilities to breaking point.