Sudoku Red - Sudoku Author:HINKLER BOOKS Sudoku is a type of logic puzzle that has been popular in Japan for about 20 years. However, the world has caught on to the challenge of sudoku. Sudoku means ""single number"" in Japanese, but the puzzles are also known as ""Number Place"" in the United States. Despite using numbers, this is not a mathematical puzzle. Logic skills and a lot ... more »of time and patience are needed to solve sudoku.« less