Paul Stephens's collection of one hundred fifty new puzzles will keep sudoku addicts going for a long time. Even the easiest ones at the beginning offer some significant challenges, if not with the puzzles themselves but with the time limitations he provides for "improver," "expert," and "genius." The puzzles are unusually well devised, and they are printed on top quality paper, so that if you, like me, may have to do a particularly challenging puzzle three times before you finally figure out all the tricks, you can erase and then re-do, without any problems. Erasing is clean, without any residue left on the eraser, and the puzzle is so "new"-looking that I defy anyone to realize that this is a re-do.
I've been a sudoku addict for about three years, doing at least one puzzle a day, and I was hoping that this book would provide me with some the techniques that the really great puzzle solvers use to work on a solution when they hit gridlock, but I was disappointed, not with the puzzles, but with the author's unusually arcane descriptions of the sudoku strategies which most of us do automatically. Spending time trying to translate what I have been doing automatically, into the author's pre-established vocabulary is annoying, when the need to do this is based on the author's unusual labeling and not on the technique itself.
I finally decided to just do the puzzles, the way I normally do. I've learned a lot about the math and strategy from doing the successive Tom Sheldon series (which I strongly recommend, regardless of level of expertise), and knowing the complex names that Stephens applies to the usual sudoku strategies is not important to me. In fact, I find most of them LESS helpful than just following instinct.
This is one of the best books I've found in terms of the quality of the puzzles, but if you are hoping to improve your skills as a result of this book, you may be disappointed. The author provides graphic examples for the strategies he suggests, but the scope of these and the ability of the puzzler to apply them to future use is so limited that I finally gave up. (I've never quite figured out what the A and B in his examples represent because the whole puzzle is not shown, and I can't see his suggestions in total context!) I've found that the techniques I already have from the Tom Sheldon series have stood me in good stead, however, and I have totally enjoyed, and even admired, Stephens's puzzles. n Mary Whipple
The Big Sudoku Brain Workout: 150 Puzzles for a Younger Mind, Book One, by Tom Sheldon
Sudoku Genius: 144 of the Most Fiendish Puzzles Ever Devised, Book Two, by Tom Sheldon
Sudoku Master Class, Book Three, by Tom Sheldon
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