In Japan, the term Sudoku is copyrighted. It was coined by Maki Kaji, president of Nikoli, a company that publishes puzzle books. The Japanese, however, still refer to the puzzle by it’s original name – Number Place. Sudoku means digit-single in Japanese.
By the way, Sudoku did not originate it Japan. The popular puzzle was invented by an American architect, Howard Garns and first published as Number Place in the May 1979 issue of Dell Pencil Puzzles and Word Games. In Japan, it was first published by the monthly Nikoli magazine.
Sudoku gained worldwide popularity because of the efforts of Wayne Gould who not only convinced The Times UK to publish it but also developed a program that would churn out countless puzzles of specified difficulty. Gould was also responsible for taking Sudoku to the United States where it was published in several daily newspapers across the country.
It costs about $1.36 per year to charge the iPad every other day. [more...]