Editing Sudoku (section)

{{Short description|Logic-based number-placement puzzle}}
{{Distinguish|text=[[Sodoku]] (the disease)}}
{{Use mdy dates |date=August 2013 |cs1-dates=sy}}
{{Multiple image
| direction = vertical
| align = right
| image1 = Sudoku Puzzle by L2G-20050714 standardized layout.svg
| image2 = Sudoku Puzzle by L2G-20050714 solution standardized layout.svg
| width = 250
| caption1 = A typical Sudoku puzzle
| caption2 = The solution to the puzzle above
| alt1 = A typical Sudoku puzzle, with nine rows and nine columns that intersect at square spaces. Some of the cells are filled with a number; others are blank cells to be solved.
| alt2 = The previous puzzle, showing its solution.
}}
'''Sudoku''' ({{IPAc-en|s|uː|ˈ|d|oʊ|k|uː|,_|-|ˈ|d|ɒ|k|-|,_|s|ə|-}}; {{langx|ja|数独|sūdoku|digit-single}}; originally called '''Number Place''')<ref name="time magazine">{{cite web |last=Grossman |first=Lev |title=The Answer Men |url= http://www.time.com/time/magazine/article/0,9171,2137423,00.html |archive-url= https://web.archive.org/web/20130301013815/http://www.time.com/time/magazine/article/0,9171,2137423,00.html |url-status= dead |archive-date= March 1, 2013 |newspaper=[[Time (magazine)|Time]] |location= New York |access-date=March 4, 2013 |date=March 11, 2013}}{{registration required}}</ref> is a [[logic puzzle|logic-based]],<ref>{{cite news |last=Arnoldy |first=Ben |title=Sudoku Strategies|work=[[The Christian Science Monitor]]}}</ref><ref>{{cite news|last=Schaschek|first=Sarah|title=Sudoku champ's surprise victory |date=March 22, 2006 |newspaper=The Prague Post |url= http://www.praguepost.com/P03/2006/Art/0323/news5.php |access-date=February 18, 2009 |archive-url= https://web.archive.org/web/20060813145953/http://www.praguepost.com/P03/2006/Art/0323/news5.php |archive-date = August 13, 2006}}</ref> [[combinatorics|combinatorial]]<ref>{{cite conference
 | last1 = Gradwohl | first1 = Ronen
 | last2 = Naor | first2 = Moni
 | last3 = Pinkas | first3 = Benny
 | last4 = Rothblum | first4 = Guy N.
 | editor1-last = Crescenzi | editor1-first = Pierluigi
 | editor2-last = Prencipe | editor2-first = Giuseppe
 | editor3-last = Pucci | editor3-first = Geppino
 | contribution = Cryptographic and Physical Zero-Knowledge Proof Systems for Solutions of Sudoku Puzzles
 | doi = 10.1007/978-3-540-72914-3_16
 | pages = 166–182
 | publisher = Springer
 | series = Lecture Notes in Computer Science
 | title = Fun with Algorithms, 4th International Conference, FUN 2007, Castiglioncello, Italy, June 3-5, 2007, Proceedings
 | volume = 4475
 | year = 2007| isbn = 978-3-540-72913-6
 }}</ref> number-placement [[puzzle]]. In classic Sudoku, the objective is to fill a 9&nbsp;×&nbsp;9 grid with digits so that each column, each row, and each of the nine 3&nbsp;×&nbsp;3 subgrids that compose the grid (also called "boxes", "blocks", or "regions") contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a [[well-posed problem|well-posed]] puzzle has a single solution.

French newspapers featured similar puzzles in the 19th century, and the modern form of the puzzle first appeared in 1979 [[puzzle book]]s by [[Dell Magazines]] under the name Number Place.<ref name=Smith /> However, the puzzle type only began to gain widespread popularity in 1986 when it was published by the Japanese puzzle company [[Nikoli (publisher)|Nikoli]] under the name Sudoku, meaning "single number".<ref>{{cite journal |title=Unwed Numbers |first=Brian |last=Hayes |journal=American Scientist |volume=94 |issue=1 |year=2006 |pages=12–15 |doi=10.1511/2006.57.3475}}</ref> In newspapers outside of Japan, it first appeared in ''[[The Conway Daily Sun]]'' (New Hampshire) in September 2004, and then ''[[The Times]]'' (London) in November 2004, both of which were thanks to the efforts of the Hong Kong judge [[Wayne Gould]], who devised a [[computer program]] to rapidly produce unique puzzles.