Sudoku Briefing

Taken from The Week Magazine, Jan 20, 2006, Vol 6, Iss 242, pg 13

A year ago, Sudoku was almost unknown outside of Japan. How did it become so big, so fast?

How popular is Sudoku: It's a monster. Barely a year after its introduction to the West, this unassuming little puzzle can now be found in more than 140 newspapers around the world, including at least 30 in the United States. Amazon.com sells 193 Sudoku books, ranging from Su Doku for Dummies to Killer Su Doku (spelling varies by publisher). In a typical week, there are 7 Sudoku books on the USA Today top 150 best-sellers list. Fanatics can also buy Sudoku calendars, board games, and jigsaw puzzles, and download Sudoku grids to their mobile phones. Psychologist Susan Blackmore calls Sudoku a classic meme, an idea that spreads rapidly from one person to the next. "It is using our brains to propagate itself across the world like an infectious virus."

Why did it catch on: "The beauty of Sudoku is that it is so easy to grasp the concept, yet it has depth," says Nobuhiko Kanamoto of the Japanese puzzle publisher Nikoli. Every Sudoku puzzle starts with a nine-by-nine grid, subdivided into nine three-by-three regions. The goal is to fill the 81 squares with numbers from one to nine in such a way that each row, column, and three-by-three region contains exactly one of each number. Each puzzle starts with a certain number of squares already filled in; how many is one of the factors that determines the level of difficulty. An average puzzler can do an easy grid in 10 minutes, while a tricky one might take an hour or more. One thing that makes the puzzles appealing is that despite all the numbers, there's no arithmetic required. Indeed, there are versions for children that use pictures instead of numbers. Solving a Sudoku is basically a matter of scanning the grid for patterns. A true Sudoku can have only one possible solution, and it is unforgiving of mistakes. Catch an error too late and you often have to erase everything and start from scratch.

Who came up with this: Not the Japanese. Modern Sudoku began life in the United States as Number Place, an occasional feature of Dell puzzle magazines in the late 1970s. The puzzle was imported to Japan in 1984 by Nikoli's Kanamoto, who tweaked it slightly and renamed it Suuji Wa Dokushin Ni Kagiru, or The Numbers Must be Single. Sudoku—as it was soon being called—had an advantage in Japan that Number Place did not have in the U.S.: The Japanese alphabet is poorly suited to crossword puzzles, so Sudoku was able to take root with little competition. But if Japan didn't invent Sudoku, America can't take complete credit either. Sudoku evolved from Latin squares, which was created by Swiss mathematician Leonhard Euler in 1783.

How did it get back to America: In 1997, a 52-year-old New Zealand judge named Wayne Gould, who was living in Hong Kong, became hooked on Sudoku during a trip to Tokyo . He spent the next six years writing a computer program that could create the puzzles. In October 2004, he pitched Sudoku to the London Times. "I turned up unannounced at the Times like an old-fashioned traveling salesman," Gould says. The newspaper's features editor, Mike Harvey, asked an aide to send Gould away. "But he said he was too busy so I went down myself," Harvey says. "It took about two minutes for him to persuade me." It helped that Gould was offering to give his puzzle away for free. All he wanted in return was a plug for his Web site, Sudoku.com, where he sells his computer program for $14.95. The Times began running Sudoku in November 2004. Three days later, the London Daily Mail had its own version. Next, Gould brought his pitch to the U.S. He was turned down by USA Today in December 2004, but five months later, after the craze had swept Europe, he landed it in the New York Post. USA Today began publishing its own Sudokus two months later. So far, Gould has made well over $1 million through his site.

Who is churning out all these puzzles: Computers. Gould's work was not hard for more seasoned programmers to imitate. Before computers, it would have been impossible to produce daily Sudoku grids, which is another reason the puzzle first took off in Japan in the 1980s. The London Guardian claims its Sudokus are constructed by hand and "contain almost imperceptible witticisms and symmetrical patterns which enhance the pleasure of completing them." But experts scoff at such hype, noting that the number of possible Sudoku grids has been calculated at 6,670,903,752,021,072,936,960. "Don't believe people when they tell you that their Sudoku puzzle has been personally handcrafted by Japanese slaves," says Michael Mepham, author of Sudoku: The Hot New Puzzle Craze. "It's all done by computer, I assure you."

What makes them so addictive: Everyone has a theory. "There's something eternal about the simple grid," says Gould. "It's a battle between you and the puzzle, with no intervening dictionaries, reference books, computers, or other aids." Psychologists say solving the puzzle creates a high almost like a drug. Filling in the correct numbers in each Sudoku puzzle is most difficult at the beginning, but puzzlers then get a sudden rush as a tipping point is reached; at the end, the numbers almost fill themselves in. This gratification is enormously potent for some people. Others say puzzlers find escape in deep concentration. "In a small, minuscule way, solving a puzzle gives us relief from the larger philosophical puzzles," says Marcel Danesi, a professor of semiotics at the University of Toronto. For all these reasons, says Nikoli's Kanamoto, "You can no more get bored of Sudoku than you can get bored of reading novels."