The objective of Sudoku is to fill the grid with the numbers 1 to 9, such that each
row, column and 3x3 sub grid contains each of the numbers from 1 to 9.
Each Sudoku game starts off with some squares already filled in, you must fill in
the rest.
You can also right click a cell to 'pencil in' numbers that you think may go there.
This can be useful if you are not excatly sure of what number belongs in a particular
cell.
Sudoku is a Japanese word meaning "single number". An early version of Sudoku known
as Latin Squares was devised by the 18th century Swiss mathematician Leonhard Euler.
Euler had come up with a grid in which each symbol could only appear once in each
row or column.
By the late 1970s, Dell Magazines had began publishing a puzzle called "Number Place",
or what we now call Sudoku puzzles. These Sudoku puzzles were developed by Howard
Garns, and were based on Euler's concept.
By the mid 1980s, Japanese puzzle maker Nikoli Inc. began publishing the puzzles,
and gave Sudoku its current name.
In 2004 The Times newspaper in London began publishing daily Sudoku puzzles. Within
a few months, several other Brithish newspapers were publishing Sudoku puzzles.
By 2005 several newspapers in the US were also publishing their own Sudoku puzzles.