The
difficulty lies in that each vertical nine-square column,
or horizontal nine-square line across, within the larger square,
must also contain the numbers 1-9, without repetition or omission.
The creator
of a particular puzzle will have filled in several of the
squares to set you on your way. The rest is up to your ability
to employ simple logic. Addicts claim a factory hand can be
as adept at Sudoku. as a university professor.
Although
Sudoku is a Japanese import, its roots lie in the work of
an 18th-century Swiss genius. Leonhard Euler, who was born
in Basle in 1707 and has been described as one of the greatest
mathematicians of all time.
Plagued
by eyesight problems that eventually led to blindness, Euler
nevertheless produced formulas in every branch of mathematics,
wrote 886 books and papers and also found the time and energy
to father 13 children.
But the
idea that is saluted every day, albeit unknowingly, by fans
of Sudoku is Euler's 'Latin Squares', which he introduced
in 1783 as a 'nouveau espece de carres magiques', which translates
as 'a new kind of magic squares'.
This
was a grid of equal dimensions in which every number or symbol
occurs once in each row or column. It differs from the Sudoku
grid only in that the latter is subdivided into blocks of
nine.
Sudoku's
modern worldwide vogue can be traced back to the early 1980s,
when it appeared in an American puzzle magazine under the
name of the 'Number Place'game.
This
was noted by the Japanese puzzle magazine publishers Nikoli.
Its attraction was that it transcended language barriers and,
in any case, Japanese does not lend itself to crosswords because
of the nature of its alphabet. Nikoli copied the idea and
introduced it to its readers in 1984.
It was
such a hit that there are now five Sudoku magazines published
in Japan each month, with a total circulation of 660,000.
The Sudoku name is registered as a trademark in Japan, so
rivals run it under the original U.S. name of Number Place.
Thanks
to its reliance on numbers rather than words, Sudoku has been
included in several World Puzzle Championships. The phenomenon
came to the attention of the Mail last year and since then
readers have been given a Sudoku puzzle to solve each weekday.
Purists say there should be only one solution to any Sudoku
puzzle, although that is not always the case.
It has been said that in a classic 81-square Sudoku grid,
the fewest number of squares that can be filled in by the
creator for the reader to have any chance of finishing the
puzzle is 19. But no one seems yet to have calculated how
many Sudoku variations there could be. Some websites claim
the possibilities are infinite, though mathematically, that
surely cannot be so. |
