History of Sudoku
Sudoku first launched in 1979 under the name 'Number Place' by Howard Garns. It was originally a simple, partially completed grid that had to be finished by the player. In 1984, the puzzle was introduced to Japan by Nikoli in the paper Monthly Nikolist and was named as Kaji Maki.
Over the years, the game has evolved and expanded across the world. A few periodicals such as the Arahi Shimbun still publish this puzzle. Even newspapers like Times, New York Post, USA Today, Washington Post and San Francisco Chronicle also publishes the puzzle. Electronic versions have also been developed recently for computers and PDA use.

The Game
Sudoku is a logic based placement puzzle. It is mostly a 9-by-9 grid made up of 3-by-3 subgrids. Some cells already with given numbers, aim of the game is to enter numerical digit from 1 to 9 in each cell. Each number in the solution occurs only once in each of three "directions". Simply mean, every row, every column and every 3-by-3 subgrid should contain digits 1 to 9 only.