The major appeal of sudoku and other Japanese logic puzzles is attributed to their simple rules and the application of logic without special knowledge of words or math. As a classic puzzle-type, logic puzzles can range from fairly easy to fiendishly difficult. The merits of these brainteasers are cited as follows: satisfaction from solving or completing something difficult; prevention of memory decline; development of logic skills; and pure mental entertainment.
Although Japanese have developed many types of logic puzzles for the last twenty years, the most common ones found in puzzle magazines are the following: sudoku, kakuro, nonogram, slither link, and divide by squares. (by Diana Lee, November 1, 2005, Uniorb: Asian Trend: Japan)