Sudoku

Sudoku, originally called Number Place, is a logic based, combinatorial number placement puzzle. In classic Sudoku the solver fills a 9 by 9 grid with digits so that every column, every row, and each of the nine 3 by 3 boxes that make up the grid contains every digit from 1 to 9, starting from a partially completed grid that has exactly one solution when the puzzle is well posed. French newspapers printed similar puzzles in the nineteenth century, and the modern form of the puzzle first appeared in 1979 in puzzle books published by Dell Magazines under the name Number Place, but it only became widely popular after the Japanese puzzle company Nikoli published it in 1986 under the name Sudoku, meaning single number. Outside Japan it first appeared in an American newspaper, the Conway Daily Sun, in September 2004, and then in The Times of London that November, both thanks to the Hong Kong judge Wayne Gould, who wrote a computer program to generate unique puzzles quickly.