Gould plays the numbers for success

At first glance it appears to be just a simple grid containing a few numbers. But dig a little deeper and it's clear there's much more to the curious numerical puzzle that's occupying minds around the world.

Called Sudoku, the puzzle appears in hundreds of newspapers every day. Elbowing in on the patch usually occupied by crosswords, it's attracted a growing base of enthusiastic fans. Add a range of best-selling books, computer programs and hundreds of Internet sites and the result is a fully fledged phenomenon.

The puzzle's appeal lies in its simplicity. Rather than requiring sophisticated mathematical skills, players need only posses a logical mind and patience. Each puzzle is solved when the numbers 1 to 9 are placed inside a 3 by 3 grid. Each box within the grid contains nine smaller squares and the numbers must be placed so that each digit appears only once in each row, column and group of 9 squares.

Although they first appeared in the 1970s, the massive global attention now focused on the puzzles can be traced to one man -- Wayne Gould.

A 60-year-old former criminal judge from New Zealand, Gould came across his first puzzle in a Japanese bookstore in 1997.

"I picked up this book of what I thought was crosswords, but it turned out to be Sudoku puzzles," he told CNN. "And I'm very glad it did turn out to be Sudoku puzzles because I was gripped as soon as I had done the first two or three."

Enthralled with its elegant simplicity, Gould set about writing a computer program that could generate the puzzles and created a method of ranking puzzle difficulty, giving them labels from 'easy' to 'very difficult.'

Then, armed with a selection of examples, Gould approached The Times newspaper in London, suggesting they consider publishing them on a daily basis. The paper agreed and, in 2004, the worldwide love affair with Sudoku took off.

Now, when many people his age are considering retirement, Gould shows little sign of slowing things down. Constantly on the move, he operates his software company Pappocom from bases in New Zealand, the United States and Hong Kong.

Gould's business model for Sudoku is also interesting. Rather than charging newspapers to publish the puzzles, he allows them to do so for free, in exchange for promoting his compendium books and computer program.

Although reluctant to reveal just how well he has done from Sudoku, it's likely the little puzzle is paying considerably better than his former career in law. Gould's puzzle books have already notched up sales in the millions in markets around the world.

Sudoku is also proving something of a hit with younger people. In an age where video games, television and the Internet provide much of the entertainment options for youth, the grids are growing in popularity.

"It doesn't depend on language, so it's been able to spread across national and cultural boundaries as if they weren't there," says Gould.

The logical reasoning required to complete Sudoku puzzles makes them appealing for teachers and parents keen to stimulate young minds. With this in mind, a range of board game variants and even a version that can be played on mobile phones is now on the market.

Although unlikely ever to completely replace crosswords, Sudoku is certainly here to stay -- it's wildly enthusiastic fan base will see to that.

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