You would imagine that with such a name this puzzle originated in Japan, but it has been around for many years in the United States and in the UK. However, the Japanese found an example under the title "Number Place' in an American magazine and translated it as something quite different: su meaning number and doku meaning single unit. It immediately caught on in Japan where number puzzles were much more prevalent than word puzzles. Crosswords don't work very well in the Japanese language. To complete the Sudoku puzzle requires a lot of patience as well as the ability to think logically. The...