Why do nine little numbers matter so much to so many? From UK to Japan and back, Sudoku has conquered the puzzle pages of the world's newspapers. This hour on Here on Earth: Radio Without Borders, Jean Feraca and her guests go behind the grid.
- Will Shortz, crossword editor of The New York Times, puzzle master for NPR's Weekend Edition Sunday
- Andrew Stuart, Sudoku columnist in the Weekend section of the Daily Telegraph
- Gideon Greenspan, Internet developer, founder of Web Sudoku