History

Su doku (Japanese: , sū doku)

A couple of millennia ago, the Chinese had the "magic square," in which the sum of every row or column of numbers organized in a square grid was identical. In 1783, the Swiss mathematician Leonhard Euler made the Latin Square: N x N grids which have all the numbers from 1 to N appearing exactly once in each row and column. Because Euler used Greek letters, these grids were often called "Graeco-Latin Squares".

The first appearance of the modern su doku puzzle was in the May 1979 issue of Dell Pencil Puzzles & Word Games (issue #16) on page 6 under the title of "Number Place". The original instructions were: "In this puzzle, your job is to place a number into every empty box so that each row across, each column down, and each small 9-box square within the large square (there are 9 of these) will contain each number from 1 through 9. Remember that no number may appear more than once in any row across, any column down, or within any small 9-box square; this will help you solve the puzzle. The numbers in circles below the diagram will give you a head start – each of these four numbers goes into one of the circle boxes in the diagram (not necessarily in the order given)."

Click here to download these two puzzles.

Will Shortz, the crossword editor of the New York Times, researched who created this unique puzzle. He knew that "Number Place" puzzles had appeared in Dell Magazines, and went through his collection to find the first. Dell listed no author, but the name Howard Garns always appeared in the contributor's list of any issue containing a "Number Place" puzzle. Also, Garns' name did not appear in any issue lacking a Number Place, which confirmed that Garns was indeed the creator of this puzzle.

Howard Garns made many Number Place puzzles for Dell and simplified the rules to those used today – fill in the grid so that every row, column, and 3 x 3 box contains the digits 1 through 9. In those days the puzzle attained a fairly small, but devout following. Further research revealed that Howard Garns was a retired architect who created the puzzle at age 74. Howard Garns died in Indianapolis, Indiana in 1989, and therefore never got a chance to see his creation become the global phenomenon that it is today.

In April 1984, Japan's puzzle group, Nikoli, discovered Dell’s Number Place and presented it to their Japanese audience in the puzzle paper Monthly Nikolist. They first named it "suuji wa dokushin ni kagiru", meaning "the numbers must be single" or "the numbers must occur only once". Kaji Maki, the president of Nikoli, felt the title was too long and abbreviated it to su doku. "Su" means number and "doku" means single. He then trademarked the name.

However, it wasn't until 1986, when Nikoli made the puzzles with symmetrical patterns and reduced the number of given clues, that su doku became one of the best-selling puzzles in Japan. As the puzzle grew in popularity, other companies stayed with the non-trademarked name of "nanpure", being short for "nanbaa puresu" or "Number Place". Even today, many Japanese puzzle magazines spell out "Number Place" in English. In the United States and elsewhere, it's called su doku.

At the end of 2004 Wayne Gould, a retired Hong Kong judge as well as a puzzle fan and a computer programmer, visited London trying to convince the editors of The Times to publish su doku puzzles. Gould had written a computer program that generated su doku puzzles of different difficulty levels, but had requested no money for them. The Times decided to try the puzzle and on 12 November 2004, published their first su doku puzzle.

The publishing of su doku in the London Times was just the beginning of an enormous craze that quickly spread all over Britain and its affiliate countries of Australia and New Zealand. Three days later The Daily Mail began publishing su doku puzzles, titled as "Codenumber". The Daily Telegraph of Sydney followed on 20 May 2005. By the end of May 2005, the puzzle was regularly published in many national newspapers in the UK, including The Daily Telegraph, The Independent, The Guardian, The Sun and The Daily Mirror.

In July 2005, Channel 4 included a daily su doku game in their Teletext service and Sky One launched the world's largest su doku puzzle – a 275 foot (84 meter) square puzzle, carved in the side of a hill in Chipping Sodbury, near Bristol. This puzzle later proved to be a huge embarrassment for Sky One when it was revealed to have 1905 different solutions to it.

Click here to download this puzzle.

The BBC Radio 4's Today began reading numbers aloud in the first su doku radio version. A famous British celebrity, Carol Vorderman, wrote the book "How to do Sudoku", which quickly became a best-selling book in the country. Even the Teachers magazine, which is backed by the government, recommended su doku as brain exercise in classrooms and suggestions have been made that su doku solving is capable of slowing the progression of brain disorder conditions such as Alzheimer's.

In April 2005, su doku travelled full circle and came back to Manhattan as a regular feature in the New York Post. On Monday, 11 July 2005, the su doku craze spread to other parts of the USA when both The Daily News and USA Today launched su doku puzzles on the same day. In both cases the su doku puzzles replaced traditional crosswords and bridge columns.

Today there are su doku clubs, chat rooms, strategy books, videos, mobile phone games, card games, competitions and even a su doku game show. Su doku has also sprung up in newspapers all over the world and is commonly described in the world media as "the Rubik's cube of the 21st century" and as the "fastest growing puzzle in the world".

 

References:
http://en.wikipedia.org/wiki/Sudoku
http://www.conceptispuzzles.com/articles/sudoku/
http://www.maa.org/editorial/mathgames/mathgames_09_05_05.html http://www.skyone.co.uk/programme/pgefeature.aspx?pid=48&fid=129