Learn to solve beguiling brain teasers faster with this superb how-to guide.
Most aficionados struggle through Sudokus on nothing more than untutored brain power, but debut author Klein offers a systematic way to efficiently analyze these ubiquitous math puzzles and suss out solutions. He begins with the basics of the deceptively simple puzzle: a nine-by-nine grid of squares, subdivided into nine three-by-three boxes, with some of the squares filled in. He tasks the puzzler with filling in the rest so that each nine-square row, column, and box includes the numbers one through nine with no repetitions. Then he introduces the key methodology of “candidates”—writing down the possible numbers that could fit in each square to help spot clues that allow the candidate numbers to be ruled out until only one is left for each square. (Most of Klein’s practice puzzles do the first step by already having the candidates printed in the blank squares; purists will object to this crutch, but many readers will be happy to outsource the tedious number crunching.) Filling in candidate numbers pays off by making it easy to see useful patterns, which the author explains in an engaging, easy-to-read style. These range from simple repeated pairs and triplets of candidate numbers that enable candidates in other squares to be eliminated to more abstract and diffuse spatial-numerical patterns like “the X-wing,” “the swordfish” and its gangly comrade “the jellyfish,” and the subtly holistic grouping called the “unique rectangle.” While cunning, these patterns and their associated solving strategies are easy to learn and work astonishingly well; using them, and with the candidate lists handily reducing cumbersome chains of logical deduction to simple pattern-recognition searches, readers should immediately be able to solve Sudokus much faster and to tackle harder puzzles. Klein includes a trove of hundreds of Sudokus, from easy to expert level, and keeps it crazy by throwing in Sudokus that use letters instead of numbers as well as some interesting variants of his own device that have coded phrases and math equations jumbled in the squares. This is the best Sudoku guide in print and should give fans plenty of fuel for their addiction.
A fine primer that should dramatically upgrade readers’ Sudoku chops.