A leading professor is sucking all the fun out of the puzzle phenomenon — by revealing a formula to solve any Sudoku problem. James Crook, an emeritus professor in South Carolina, will be publishing his “pen-and-paper algorithm for solving Sudoku puzzles” on the web-site of the American Mathematical Society.
While his paper runs to nine pages of detailed argument, the algorithm boils down to five logical steps.
Not everyone would agree. Since the introduction of the numerical puzzle in London’s The Times in 2004, sudoku has taken quiz fans by storm. It has appeared on Web sites, cellphones and in newspapers.
The puzzles are generally grids of 81 squares, nine across and nine down. Some boxes have a number filled in; the rest are blank. Players must fill in the blank squares with numbers between 1 and 9 without repeating any numbers in a row, column or the nine interior 3-by-3 boxes of the puzzle.
This weekend, in the face of mounting criticism that he is taking all the fun out of the puzzle phenomenon, the former Winthrop University don declined to discuss what he describes as a “trivial puzzle”.
Fans are aghast. Colin Dexter, author of the Inspector Morse crime novels and a puzzle enthusiast, said: “I’m sorry to hear somebody’s discovered how to do it. It’s like using a computer program to work out crossword anagrams - it takes all the fun and struggle out of it.” Nina Pell, a 21-year-old mathematics student at Sheffield University, who has twice won The Times UK National Sudoku championship, said: “The method is similar to my own Sudoku-solving strategy and confirms I’m solving it the correct way.”
Dr Gareth Moore, who compiles puzzles for Sudoku Pro magazine, said: “Crook’s algorithm might work, but the fun of Sudoku
is the logical thinking by which you turn an intimidating problem into an enjoyable brainy exercise.”
The Crook algorithm is the first mathematical proof of how to solve the puzzle. However, all is not lost. Crook’s system requires players to mark up empty cells in a Sudoku grid with all possible remaining numbers and, by comparing number sets, to labour through a “tree” of options that eventually produces a solution. The drawback: it takes ages — typically an hour. Yet through logic and intuition, most Sudoku puzzles can be solved in 20 minutes or less. Since The Times introduced Sudoku in 2004, 3mn Britons hav become players.
