mySudokuEngine, Free Sudoku Software
Sudoku is a logic game(*) born in Japan in the early 1980s.
It quickly became popular in its home country,
and then spread internationally since 2005.
The reasons for its success are obvious, simple rules and a challenge to the player's logic and concentration.
In its original version, it is played with numbers, but mathematics has nothing to do with it.
The numbers are simply used as symbols to compose a puzzle in a 3x3 grid of 'sub-grids' of 3 rows and 3 columns.
The rules, as mentioned, are simple,
The numbers must be arranged in such a way as to respect three basic rules:
1) In each (vertical) column of the grid,
all 9 numbers must appear without repetition;
2) In each (horizontal) row of the grid,
all 9 numbers must appear without repetition;
3) In each 3x3 'sub-grid'
all 9 numbers must appear without repetition.
The game normally begins with a few boxes containing a number.
This initial form is obviously followed by all sorts of variations.
The best-known is to increase the size of the grid and 'sub-grids',
adding letters to the numbers to complete the required set of symbols.
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(*) The logic of Sudoku has its roots in the Latin squares
studied by the Swiss mathematician Leonhard Euler (Euler) in the 18th century.
The classic 9x9 Sudoku is a special case of a Latin square of order 9,
with the added constraint that the numbers from 1 to 9 must not repeat, even within the 3x3 'sub-grids'.
