Sudoku Puzzle Details - Abstract
Sudoku, sometimes spelled Su Doku, is a logic-based placement puzzle, also known as Number Place in the United States. The aim of the canonical puzzle is to enter a numerical digit from 1 through 9 in each cell of a 9x9 grid made up of 3x3 subgrids (called "regions"), starting with various digits given in some cells (the "givens"). Each row, column, and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability. Although first published in a U. S. puzzle magazine in 1979, Sudoku initially caught on in Japan in 1986 and attained international popularity in 2005.
Sudoku Puzzle Details - Introduction
The name Sudoku is the Japanese abbreviation of a longer phrase, "suji wa dokushin ni kagiru," meaning "the digits must remain single"; it is a trademark of puzzle publisher Nikoli Co. Ltd in Japan.
The numerals in Sudoku puzzles are used for convenience; arithmetic relationships between numerals are absolutely irrelevant. Any set of distinct symbols will do; letters, shapes, or colours may be used without altering the rules (Penny Press' Scramblets and Knight Features Syndicate's Sudoku Word both use letters). Dell Magazines, the puzzle's originator, has been using numerals for Number Place in its magazines since they first published it in 1979. Numerals are used throughout this article.
The attraction of the puzzle is that the completion rules are simple, yet the line of reasoning required to reach the completion may be complex. Sudoku is recommended by some teachers as an exercise in logical reasoning. The level of difficulty of the puzzles can be selected to suit the audience. The puzzles are often available free from published sources and also may be custom-generated using software.