What is Sudoku?

It's big in Japan, huge in Europe and sweeping America. Now, Sudoku (Japanese for "single number") lands in the Chicago Sun-Times.

• Sudoku for Feb. 9

• Sudoku for Feb. 8

• Sudoku for Feb. 7

• Sudoku for Feb. 6

• Sudoku for Feb. 4

• Sudoku for Feb. 3

For tips and solutions visit www.sudoku.com