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True test of genius or monumental waste of time? Can you solve the hardest ever Sudoku?
By PAUL MILLIGAN
PUBLISHED: 23:27 GMT, 29 June 2012 | UPDATED: 10:51 GMT, 30 June 2012

Fancy yourself as a Sudoku whizz? Can you complete the tasks faster than all your friends? Well, now comes the ultimate test - the world's most difficult puzzle.

Finnish mathematician Arto Inkala spent three months designing a Sudoku grid with only one solution.
Inkala has warned any potential challengers only the quickest and brightest minds would be able to solve it.

Test your skills: Is this the world's hardest Sudoku challenge?

Sudoku has become a daily fixture in many people's lives since becoming popular in the last 10 years.
Now common in many newspapers across the world, the puzzles are often graded in difficulty. With a rating of one being for beginners and those rated with a five taking a much longer time to complete.
 
Mr Inkala claims his monster puzzle, hosted by www.efamol.com, is a whopping 11 on the difficulty rating.
A spokesperson for Efamol said: 'Mr Inkala was thought to have created the world's hardest Sudoku puzzle in 2006 for the website Al Escargot. It was so popular that he made it even harder in 2010.
'Now he has created his hardest one yet which will certainly stretch even seasoned Sudoku solvers.
'We don't believe the puzzle is impossible because Mr Inkala has solved it himself. But we haven't had any reports of anyone else completing it yet.'
If you want to give the Sudoku a go, fear not, we have the answer if you get stuck, here it is.