## Tuesday, October 24, 2006

### The History of Sudoku (Logic9)

It’s hard, perhaps impossible, to pinpoint the exact time and place in which the original concept of Sudoku (Japanese: 数独, sūdoku) began, but it seems to be related to the appearance of the first Magic Squares.

The idea of the magic square was transmitted to the Arabs from the Chinese, probably through India, in the eighth century.

It appears that Magic Squares may have introduced to Europe through Spain by Abraham Ben Meir ibn Ezra, a Hispano-Jewish philosopher and astrologer.

The Swiss mathematician and physicist Leonhard Euler (1707-1783) presented to the St. Petersburg Academy on October 17, 1776, how to construct Magic Squares with a certain number of cells, in particular 9, 16, 25, and 36.

This particular type of puzzle as we know it was first published in the late 1970’s in Math Puzzles and Logic Problems magazine by Dell Magazines. The name given by Dell to these puzzles was Number Place.

Dell took Euler’s Latin Square concept and applied it to a 9x9 grid with the addition of nine 3x3 sub-grids, or boxes, each containing all numbers from 1 to 9.

So, the Sudoku concept was not invented in Japan as many people may believe, but the name Sudoku was. In 1984 Nikoli, Japan’s leading puzzle creating company, discovered Dell’s Number Place and decided to present them to their Japanese puzzle fans.

The puzzles, which were first named Suuji Wa Dokushin Ni Kagiru, ("the numbers must be single" or "the numbers must occur only once") quickly became popular.

In 1986, after some important improvements were added, mainly by making symmetrical patterns and reducing the number of given clues, Sudoku became one of the best selling puzzles in Japan.

Realizing that the only problem with the Sudoku puzzles was their long name, Kaji Maki, the president of Nikoli abbreviated it to Sudoku - (Su = number, digit; Doku = single, unmarried).

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 Sudoku puzzles. Gould, that had written a computer program which generates Sudoku puzzles of different difficulty levels, demanded no money for the puzzles. The Times decided to give it a try and on November 12, 2004 launched their first Sudoku puzzle.

The publishing of Sudoku in the London Times was just the beginning of an enormous phenomenon which swiftly spread all over Britain and its affiliate countries of Australia and New Zealand.

Even the Teachers magazine which is backed by the government recommended Sudoku as brain exercise in classrooms and suggestions have been made that Sudoku solving is capable of slowing the progression of brain disorder conditions such as Alzheimer's.

In April 2005 Sudoku completed a full circle and arrived back to Manhattan as a regular feature in the New York Post. On Monday, July 11, the Sudoku craze spread to other parts of the USA.

Today there are Sudoku clubs, chat rooms, strategy books, videos, mobile phone games, card games, competitions and even a Sudoku game show.

Sudoku 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".

hoo said...

mr tan it is the first time i heard from u. i m a 10 years old boy. it is very interesting.i would like to try the puzzle.

japaw said...

Dear Mr. Tan,

The chinese has a rather interesting game, the HuaRongDao (华容道） based on the story of Caocao (曹操) and Guanyu (关羽) during the 3 kingdoms (三国). Basically it is a simple board game consisting of 10 pieces - Caocao, Guanyu and 4 officers and 4 soldiers, placed in a certain formation surrounding Caocao. The idea is to move the pieces around so that the trapped Caocao can be freed and escapted from the only opening. There are many possible scenario to set up the games and hence the many different steps in getting Caocao out.

I find the game quite stimulating especially at time when I find myself in a trap, like Caocao, and looking for ways to escape but nowhere to turn to.

The moral of the story is that there is always someone out there to lend you a helping hand, even in the case of life and death. Guanyu owed Caocao once and he lets Caocao off this time, which could have the history rewritten otherwise. This is the tradition of chinese teaching, don't push even your arch rival into corner, and knowing when to pay back sometime. Hence today many chinese worship Guanyu, also known as Guangong (关公)， for his yiqi (义气）or righteousness and royalty.

it costs only a few yuan to buy the board game in china and it is small enough to carry it in your pocket.

Hope you like the game!

Cheers!

francis

Tan Kin Lian said...

We will be organising two days in November and December to teach the public on how to play Logic9 (our version of Sudoku). Attendees will get 1 free copy of Logic9 (worth \$5).

Details will be published in Today and MyPaper and eNN. Register for www.eNN.com.sg