This is the final puzzle of the 2007 World Sudoku
Championship. As reported in the
London Times, champion Thomas Snyder solved the puzzle in a total of five
minutes, including about a minute to double-check his answer. And if you aren't
already impressed, Thomas knew that he had 10 minutes to solve this puzzle
completely in order to secure the championship—so
he actually took his time on this one!

Place the digits 1 through 9 into the
empty cells so that each digit appears exactly once in each row, column,
and in each of the nine outlined jigsaw pieces. Competitors were also
given that the digits inside the round parts of the pieces must also be
round (3, 6, 8, or 9), but this information is not required to find the
unique solution.