Leonhard Euler might not be a household name, but a small contribution of the 18th-century Basel genius is probably already in your home – sudoku.This content was published on August 20, 2005 - 17:01
This addictive test of logic has already conquered the United States, Japan and Britain and it is now creeping into Swiss newspapers and bookstores.
"Maths hardly comes into it," Professor Alberto Bersani, a mathematician at La Sapienza University in Rome and a games enthusiast, told swissinfo. "Nor does riddle-solving. What counts is logic, a quick mind and patience."
Like many successful games, sudoku is in theory incredibly simple. All you have to do is fill in the 9x9 grid, a third of which someone has kindly already done for you, so that every row, every column and every 3x3 box contains the digits one to nine.
However, in practice sudoku is up there with the Rubik's cube for sheer pencil-snapping exasperation.
Everyone can have a go as, like the Rubik's cube, sudoku leaps across language barriers. What's more, smaller grids – perhaps with colours instead of numbers – are excellent for pre-schoolers taking their first steps in reasoning.
There is a danger of snobbery from crossword fans for whom a number is something that numbs, but the comparison is unfair. Sudoku is pure logic – it's more like chess for one – and it doesn't claim to challenge your vocabulary or cultural awareness.
Sudoku grids have a long, international and not always certain history, but one thing is definite: they are not Japanese.
The puzzles were in fact invented 222 years ago by a Swiss maths genius, Leonhard Euler, who dominated 18th-century mathematics and whose collected works fill 75 volumes.
Euler was born in Basel in 1707, studied at the city's university and left aged 19 to take up his first professorship in St Petersburg.
The mathematician died in 1783, the year he devised his carrés magiques – magic squares. These 81-square grids were the proto-sudoku puzzles.
Although Euler never returned to Switzerland after leaving for Russia, the Swiss still proudly claim him as one of their own – he used to be the face of the SFr10 note – and a series of celebrations are being planned for the tercentenary of his birth in 2007.
Euler's magic squares then kept a low profile for the best part of two centuries until a crossword and puzzle magazine in New York started publishing what they called Number Place in the 1970s.
One such Number Place was spotted by a Japanese publisher, retitled sudoku (su in Japanese means "number" and doku means "single/unique") and published for the first time in Japan in 1984.
It rapidly became a huge success in puzzle-obsessed Japan, where the alphabet is not really suitable for crosswords.
The next step in sudoku's evolution occurred in 1997. Wayne Gould, a New Zealander, was browsing in a Tokyo bookshop when he spotted a sudoku grid.
Gould spent the next six years developing a sudoku-generating computer program and in October 2004 pitched sudoku to The Times newspaper in London.
The Times published Britain's first newspaper sudoku puzzle the following month and the phenomenon was born.
All British national newspapers now have daily puzzles and underground trains are crammed with commuters hunched over their papers, scribbling away.
It looks as though Swiss trams will also soon be full of passengers muttering random numbers to themselves.
Sudoku fever first struck in German-speaking Switzerland.
In May the Tages-Anzeiger newspaper published the first Swiss puzzle and since then it has become a regular in the Saturday edition. "Feedback is extremely positive," said editor Benno Schmidt.
At the end of July the tabloid Blick followed suit and now publishes two puzzles every weekday along with a prize draw. The Berner Zeitung also started published sudoku puzzles at the end of July.
The French-language Le Matin newspaper in Lausanne introduced the craze in July and Le Temps in Geneva followed a day later.
Anouch Seydtaghia at Le Temps says the puzzles were originally intended for the two summer months "but because of the positive feedback it's certainly possible that the paper will keep them".
Books about sudoku are also proving popular. Orell Füssli, one of Switzerland's largest bookshops, said a sudoku book was one of the five most sold books in July.
Swiss crossword fans needn't worry however – editors of their local newspapers have promised that sudoku grids will never usurp their corner of the paper.
swissinfo, Thomas Stephens
Sudoku was invented by Leonhard Euler, a Swiss mathematician, in 1783.
The fiendish test of logic has already conquered the United States, Japan and Britain and is now creeping into Swiss newspapers and bookstores.
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