Sudoku Strategies - Questions related to Sudoku puzzles (FAQ)
History of Sudoku and Mathematics
- What is a "Sudoku" ?
- What does it means ?
- When has it been created ?
- How many different Sudoku puzzles ?
What is a "Sudoku" ?
Sudoku is a game. Objective is to fill a grid with 9 boxes on sides with numbers going from 1 to 9 by respecting certain constraints, some numbers being already laid out in the grid.
Interest of the game lies in the simplicity of its rules, and in the complexity of its solutions. The puzzles containing the most cells filled are in general simplest, reverse not being systematically true.
What does it means ?
Name sudoku comes from Japonais ![[Su] sudoku](images/su.gif)
(sû : number) and from ![[doku] soduku](images/doku.gif)
(doku :
single).
Like all transcriptions from Japanese to English, it is possible to meet many spelling variants such as:
- Sodoku,
- So-Doku,
- So-Do-Ku,
- Suduku,
- Su-duku,
- Su-Du-Ku,
- Soudokou,
- Sou-Do-Kou,
- Soudoku,
- Sou-Doku,
- Su-Dokou,
- Sudokou,...
The translation commonly used is Sudoku or Su-Doku.
This word wastrademarked in several countries like Japan and USA. The denomation of the game used by those which do not hold the mark is then "Number places".
Regarding the pronunciation, the sudoku is pronunced sou-do-kou.
When has it been created ?
The origin of the game, based on the Latin square, goes up at the beginning of the Christian era.
In 1782, the Swiss mathematician Leonhard Euler, on the basis of Latin square, approaches the form which we know of Sudoku, with the game of the 36 officers, thus using symbols and rules more strict than Sudoku.
Grids are published at the end of the XIXème century in French newspapers, with however some rules of additional constraints to the form which we know.
It is Howard Garns, in 1979 ,which gives to the game its current form. The grids have been published in the US.
The game was introduced in 1984 in Japan under the name of Sudoku. Success was immediate.
In 2005, success is worldwide.
Learn more on : Wikipedia
How many different Sudoku puzzles ?
In 2005, two researchers proved that the number of grids was exactly of
6 670 903 752 021 072 936 960 grilles
This result was proven with an exhaustive research and was validated thereafter by other researchers. By holding account of symmetries, the number of grid strongly falls and there remain only 5 472 730 538 grids of Sudoku. While spending 10 minutes by grid, at a rate of 8 hours per day, it would be necessary for you more than 3 million years to come from there to end...
To look further, read : Wikipedia
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