Sudoku #3378

Level: Extremely Hard

 Fun Fact About 2
Actually, Sudoku isn't a Japanese game it all. It's American invented. Howard Garns created it as Number Place in 1979 but died in 1989 before Japanese publisher Nikoli got a hold of it. The game didn't really take off until 2004 though, when Wayne Gould convinced The Times in London to publish it.

Enter numbers into the empty cells so that each row, column and 3x3 box contains the numbers 1 to 9.