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Sudoku singularity by puzzle master Maki Kaji

Maki Kaji at his office
Maki Kaji at his office
TOKYO (TR) – With their 81 stacked squares, sudoku puzzles might appear ordinary, but they have become a seemingly boundless phenomenon. Found in the pages of books, magazines and newspapers and on mobile phones and the Internet, sudoku boast more than 100 million devotees across the globe.

In light of such success, the game’s founder, Maki Kaji, could be excused for feeling a degree of self-satisfaction. On the contrary, the 58-year-old president of publisher Nikoli is now attempting to preserve his original ideal for the numeric brainteaser.

“It has been more than 20 years since sudoku was established,” says gray-whiskered Kaji during an interview at his office in Tokyo’s Taito Ward. “Since then, it has been refined into various forms. Because of this and its immense popularity, people in the US and the UK are responding by asking us to produce classic sudoku puzzles.”

Kaji, a college dropout with a passion for betting on horse races, believes that computer-generated versions of the puzzle remove part of the enjoyment. The most common format contains a couple dozen digits scattered throughout a nine-by-nine grid of squares that is divided into nine smaller three-by-three grids into which the numbers 1 through 9 must be placed.

Solving a “classic,” handcrafted sudoku puzzle — the type only produced by Nikoli — involves a tacit dialogue between author and solver, according to Kaji. “To solve one requires logic,” explains the self-described “godfather” of sudoku, puffing on a cigarette. “It is not a matter of trial and error.”

Nikoli’s staff of around 20, some of whom will be hosting this month’s sudoku-themed afternoon of solving tips, contests and prizes at the Club, checks each potential puzzle, which is graded on a scale of difficulty, to ensure it has an enjoyable, step-by-step rhythm.

Roughly 80 percent of Nikoli’s sudoku are culled from submissions by readers, a policy the company has followed since it published Japan’s first puzzle magazine in August 1980. “Even back then, before the Internet, we were communicating with our customers,” says Kaji, whose company ships multiple puzzle products domestically and abroad and circulates 50,000 copies of its quarterly puzzle magazines in Japan. “We developed an interactive relationship that extended beyond magazines from overseas, which just printed a puzzle and said, ‘Solve this!’”

In 1984, he introduced a new puzzle into Nikoli’s magazines based on Number Place, a game that had appeared years before in Dell Pencil Puzzles and Word Games magazine in the United States. By 1997, when retired Hong Kong judge Wayne Gould discovered Kaji’s brainchild while browsing in a bookstore in Japan, the puzzle had been given its current name of sudoku, which generally means “single number.”

Gould subsequently developed a computer program for generating the puzzles. The Times newspaper in Britain started featuring his versions of sudoku in 2004, and it’s this event that is largely credited with prompting a wider interest in the game.

A sudoku puzzle
A sudoku puzzle
Regarding Kaji’s claim that handmade puzzles are more rewarding than their computer-fabricated counterparts, Gould generally agrees but adds that the concept is overblown with the benefits of the computer ignored. “With computer-generated puzzles, provided they are made by a reliable program, everything is purely random,” he says. “You don’t get sucked into the setter’s preferences for, say, one number over another, or one trick or trap over another. When you have human setters, you have ‘styles’ — a set of preferences adopted by the setter, perhaps consciously or perhaps subconsciously. In time, the style can become predictable, even boring. With computer-generated puzzles, every puzzle is fresh, an unknown quantity. No preconceptions will help you, no knowledge of the setter’s past puzzles will guide you.”

Nikoli commands roughly 5 percent of the world sudoku market, which today extends into approximately 70 countries. Such a small relative share can be at least partially attributed to Kaji’s failure to register a copyright.

Will Shortz, editor of the New York Times crossword puzzle and director of the annual World Sudoku Championship, to which Kaji has been invited to make a speech this April in Philadelphia, says sudoku’s success lies in its simplicity, the limitless number of puzzle combinations available and an affinity people have for completion.

“I think as human beings we like to fill up empty spaces, and sudoku shares this quality with crosswords,” explains Shortz. “It’s somehow satisfying to complete empty squares. And when you fill in the last square of a particularly difficult sudoku puzzle, you get an immense feeling of satisfaction and accomplishment.”

Kaji believes that while sudoku was initially seen as a refreshing “high-tech” curiosity from Japan, its subsequent preeminence has been due to its uncomplicated, entertaining appeal. “Sudoku is like an appetizer, or something you can eat every day,” he says. “One puzzle appears, and you solve it. Then you move onto the next, and you solve that. It’s not like a main dish, which is a real challenge.”

Although the rise of online games and puzzles hasn’t expanded the market for Nikoli, Kaji says that these new formats help to further the company’s brand image. (Nikoli now offers applications for Apple’s iPhone and iPod Touch.) What’s more, he says that the royalty-free environment in which sudoku exists outside of Nikoli’s publications allows for easy expansion. “Our next target is Africa,” he says. “I want to instill upon [Africans] the enjoyment that can be had with Nikoli puzzles.”

That pleasure, Kaji says, is derived from being able to immerse yourself in a puzzle and forget about the pressures of daily life — a crucial contrast to typical mind-training regimes. “Training makes you stressful because you feel pressure to solve something, but sudoku is different,” he says. “You can play just as long as it suits you. In that sense, it is like watching a movie.” And a blockbuster at that.

Note: This article originally appeared in the January issue of iNTOUCH, the magazine of the Tokyo American Club.