Sudoku

This is a number puzzle that has found its place alongside crossword puzzles in newspapers around the world. A very similar intellectual game was introduced in French newspapers in the 1890s, but disappeared after about 30 years. They reappeared in 1979 when such puzzles were published in America, but real popularity came when the games publisher Nikoli introduced the puzzle in Japan under the name Sūji wa dokushin ni kagiru, which means single-digit or single (as in unmarried). This was subsequently shortened to ‘Sudoku’ and patented in Japan. It marched into the mainstream when The Times published its first Sudoku in 2004. There are now Sudoku World Championships. Sudoku puzzling has been cited as a reason for missing trains or even stopping a drug trial because the jurors were more interested in finding the answers than listening to evidence!