What is the hardest Sudoku puzzle in the world?

What is the hardest Sudoku puzzle in the world? A Finnish mathematician claims to have designed the world’s most difficult Sudoku. The numerical puzzle took Arto Inkala three months to design, and it has only one solution – one that only the sharpest minds will discover, he told the Daily Telegraph.

A Finnish mathematician claims to have designed the world’s most difficult Sudoku. The numerical puzzle took Arto Inkala three months to design, and it has only one solution – one that only the sharpest minds will discover, he told the Daily Telegraph.
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