Quotes of the Day

Britain's national newspapers may disagree on politics, but they agree on the story of the season: Su Doku is here! An addictive puzzle in which the numbers 1 to 9 must occur only once in every row, column and box within a grid, Su Doku has Britons hooked.

Since its debut in the Times last November, almost every major paper in the country, desperate not to miss any chance to build circulation, has acquired a version. Tabloid variants come with celebrity endorsements and last week, after the Guardian launched its puzzle, the Times fought back with the first mobile-phone version: download 10 puzzles for $8.30. The newspaper fight began with Wayne Gould, who sold the concept to the Times last fall after almost being turned away at the door. "Even in my fantasy sequences, I didn't anticipate it would get this far!" says the 59-year-old New Zealander. Gould, a retired judge, discovered the game in a Tokyo bookstore in 1997 and spent six years developing software that can generate viable puzzles. Since then, he's syndicated Su Doku to papers in 10 countries — including Croatia, South Africa and the U.S. — with more in the pipeline.

His Su Doku book has sold over 120,000 copies, and two more are afoot. Gould admits he's been overwhelmed by the phenomenon, which fans call the 21st century's Rubik's Cube. "I don't think I could stop it if I wanted to," he says. "In the nature of addiction, it knows no national boundaries."

• JESSICA CARSEN
• Forget bingo and giveaway CDs, a Japanese puzzle is the saviour of newspaper circulation