Sudoku

Sudoku puzzles are addictive brain teasers that have been referred to as wordless crossword puzzles. They can be solved by lateral thinking alone and have been making quite an impact around the world.

Sudoku, also known as Number Place or Nanpure, is a logic-based placement puzzle. The objective is to fill the grid so that every column, every row and every 3×3 box contains the digits 1 to 9. The puzzle setter provides a partially completed grid so that there is only one solution.

Completed Sudoku puzzles are a type of Latin square, with an additional constraint on the contents of individual regions. Leonhard Euler is sometimes (incorrectly) cited as the source of the puzzle, based on his work with Latin squares.

The modern puzzle was invented by an American, Howard Garns, in 1979 and published by Dell Magazines under the name "Number Place". It became popular in Japan in 1986, when it was published by Nikoli and given the name Sudoku. It became an international hit in 2005.

The name "Sudoku" is the Japanese abbreviation of a longer phrase, "Sūji wa dokushin ni kagiru",meaning "the digits must occur only once". It is a trademark of puzzle publisher Nikoli Co. Ltd. in Japan. Other Japanese publishers refer to the puzzle as Number Place, the original U.S. title, or as "Nanpure" for short. Some non-Japanese publishers spell the title as "Su Doku".

The attraction of the puzzle is that the rules are simple, yet the line of reasoning required to solve the puzzle may be complex. The level of difficulty can be selected to suit the audience.


Go To : Sudoku solving techniques