The vast majority of sudoku puzzles that are labeled hard, expert, challenger, are not really all that difficult. And in a surprising number of cases, they are

Here it comes: a revolution in sudoku solving! This is by far the most complete guide to cracking these addictive puzzles ever produced, with tricks even the ex

Top solvers can try their hand at the One-Sided Gordonian Rectangle; Extended Gordonian Rectangle; Gordonian Polygon; and Alternating Digits. (But they can take

Even more interaction--this time used in combination with other procedures...and a lot more heavily than in the first book.

The difficulty level soars, as even more tricks get added to the mix: X-Wing; Swordfish; XY-Wing; XYZ-Wing; and the Gordonian Rectangle.