Sudoku is one of the most popular puzzles in the world, enjoyed by millions of people daily. But where did this addictive number puzzle come from? The history of Sudoku spans centuries and continents, involving Swiss mathematicians, American puzzle designers, Japanese publishers, and a retired judge from New Zealand.
This is the true story of how a simple logic puzzle conquered the world.
The Mathematical Foundations: Latin Squares
The roots of Sudoku can be traced back to the 18th century and the work of Swiss mathematician Leonhard Euler (1707โ1783). In 1783, Euler introduced a mathematical concept called "Latin Squares" โ grids where each symbol appears exactly once in each row and column.
๐งฎ Leonhard Euler (1707โ1783)
Euler was one of the most prolific mathematicians in history. His work on Latin Squares was purely mathematical โ he was interested in combinatorics and arrangement problems, not puzzles. A Latin Square is an nรn grid filled with n different symbols, where each symbol occurs exactly once in each row and once in each column.
Euler's Latin Squares form the mathematical foundation of Sudoku, though he never imagined his work would one day entertain millions of puzzle enthusiasts.
Latin Squares remained a topic of mathematical interest for nearly two centuries. They found applications in experimental design and statistics, but it wasn't until the late 20th century that someone thought to turn them into a puzzle.
The Birth of "Number Place" (1979)
The puzzle we now know as Sudoku was first published in May 1979 in Dell Pencil Puzzles and Word Games magazine under the name "Number Place". The puzzle was created by Howard Garns, a 74-year-old retired architect from Connersville, Indiana, USA.
๐๏ธ Howard Garns (1905โ1989)
Howard Garns worked as an architect in Indianapolis before retiring. He began creating puzzles as a hobby and contributed to Dell puzzle magazines. Garns took Euler's Latin Square concept and added the crucial innovation that makes Sudoku unique: the 3ร3 box constraint.
By requiring each digit to appear exactly once in each row, column, AND 3ร3 box, Garns created a puzzle that was both more constrained and more interesting to solve. Sadly, Garns was never credited by name during his lifetime โ Dell published puzzles anonymously. He passed away in 1989, never knowing his creation would become a worldwide phenomenon.
๐ Key Innovation
What distinguishes Sudoku from a simple Latin Square is the addition of the 3ร3 box regions. This constraint transforms a mathematical arrangement into a logic puzzle with a unique solving path. Garns' insight was that these overlapping constraints create interesting deductive challenges.
Japan and the Name "Sudoku" (1984)
The puzzle might have remained an obscure American magazine feature if not for its introduction to Japan. In April 1984, the Japanese puzzle company Nikoli published the puzzle in their magazine Monthly Nikolist under the name "Sลซji wa dokushin ni kagiru" (ๆฐๅญใฏ็ฌ่บซใซ้ใ), meaning "the digits must be single" or "the digits are limited to one occurrence".
๐ฏ๐ต Nikoli's Contribution
Nikoli, founded by Maki Kaji in 1980, is Japan's leading puzzle company. They made several important refinements to the puzzle:
- The name "Sudoku": The long Japanese name was abbreviated to "Su-doku" (ๆฐ็ฌ), combining "sลซ" (number) and "doku" (single). Nikoli trademarked this name in Japan.
- Symmetrical clues: Nikoli established the convention that the given numbers should be arranged symmetrically on the grid, making puzzles more aesthetically pleasing.
- Minimal clues: They promoted puzzles with fewer given numbers, increasing the challenge and elegance.
Throughout the late 1980s and 1990s, Sudoku became increasingly popular in Japan. Nikoli published dedicated Sudoku books, and the puzzle developed a devoted following. However, it remained largely unknown outside Japan.
The Global Explosion (2004โ2005)
The story of how Sudoku went global centres on one man: Wayne Gould, a retired Hong Kong judge originally from New Zealand.
โ๏ธ Wayne Gould (born 1945)
In 1997, while browsing a bookshop in Tokyo, Gould discovered a Sudoku puzzle book. Fascinated by the puzzle, he spent the next six years developing a computer program that could generate Sudoku puzzles of varying difficulty levels.
In 2004, Gould approached The Times newspaper in London with his puzzles. He offered them for free, asking only for a credit and a link to his website. The Times published its first Sudoku on 12 November 2004.
The response was immediate and overwhelming. Within months, Sudoku had spread to newspapers across Britain, then Europe, then the world. By 2005, Sudoku was being called "the Rubik's Cube of the 21st century".
The Times (London) publishes its first Sudoku puzzle
Other British newspapers (Daily Mail, The Guardian, Daily Telegraph) begin publishing Sudoku
The New York Post becomes the first US newspaper to publish daily Sudoku
USA Today begins publishing Sudoku
"Sudoku" is named Word of the Year by the Language Report
First World Sudoku Championship held in Lucca, Italy
The Mathematics of Sudoku
As Sudoku's popularity grew, mathematicians began studying the puzzle seriously. Several interesting mathematical facts have been established:
๐ข Sudoku by the Numbers
- 6,670,903,752,021,072,936,960 โ The total number of valid completed 9ร9 Sudoku grids, calculated by Bertram Felgenhauer and Frazer Jarvis in 2006.
- 5,472,730,538 โ The number of essentially different Sudoku grids (accounting for symmetries like rotation and reflection).
- 17 โ The minimum number of clues required for a Sudoku puzzle to have a unique solution, proven by Gary McGuire and colleagues in 2012 after years of computational research.
- 21 โ The typical minimum for newspaper puzzles, as 17-clue puzzles are extremely difficult.
The question of the minimum number of clues was a famous open problem in recreational mathematics. McGuire's team at University College Dublin used over 7 million CPU hours to prove that no 16-clue puzzle with a unique solution exists.
Competitive Sudoku
The World Puzzle Federation (WPF) organised the first World Sudoku Championship in Lucca, Italy, in March 2006. The competition brought together the best puzzle solvers from around the world.
๐ World Sudoku Championship
The World Sudoku Championship is held annually (except during the COVID-19 pandemic). Competitors solve a variety of Sudoku puzzles and variants under timed conditions. Notable facts:
- The first champion was Jana Tylovรก of the Czech Republic (2006)
- Thomas Snyder (USA) won three consecutive titles (2007โ2009)
- Japan and the Czech Republic have produced many top competitors
- The championship includes both classic Sudoku and variant puzzles
Today, competitive Sudoku continues to thrive, with national championships, online competitions, and apps like the SudokuWorldTournament.com (sudokuWT.com) bringing competitive play to mobile devices.
Sudoku Variants
The success of classic Sudoku has spawned numerous variants that add additional constraints or change the grid structure:
- Killer Sudoku: Adds "cages" with sum constraints, combining Sudoku with Kakuro
- Diagonal Sudoku: The main diagonals must also contain 1-9
- Irregular Sudoku (Jigsaw): Replaces 3ร3 boxes with irregular shapes
- Samurai Sudoku: Five overlapping 9ร9 grids
- Mini Sudoku: 4ร4 or 6ร6 grids for beginners
- Giant Sudoku: 16ร16 or 25ร25 grids for experts
Sudoku Today
More than 40 years after Howard Garns created "Number Place", Sudoku remains one of the world's most popular puzzles. It appears in thousands of newspapers, countless apps, and dedicated puzzle books. The puzzle has been credited with helping maintain cognitive function in older adults and teaching logical thinking to children.
The digital age has transformed how people play Sudoku. Mobile apps offer features that would have been impossible in print:
- Automatic candidate tracking
- Hint systems that explain solving techniques
- Global leaderboards and competitive play
- Daily challenges with identical puzzles for all players
- Difficulty ratings based on required solving techniques
๐ฑ The Digital Evolution
Modern Sudoku apps like the SudokuWorldTournament.com (sudokuWT.com) have evolved far beyond simple digital versions of paper puzzles. They incorporate technique recognition, scoring systems that reward logical play, and competitive features that connect players worldwide. The core puzzle remains unchanged, but the experience has been transformed.
Key Dates in Sudoku History
Leonhard Euler publishes work on Latin Squares
Howard Garns creates "Number Place" for Dell magazines
Nikoli introduces the puzzle to Japan as "Sudoku"
Howard Garns dies, never knowing his puzzle's future fame
Wayne Gould discovers Sudoku in Tokyo
The Times publishes first Sudoku (12 November)
Global Sudoku craze; "Sudoku" named Word of the Year
First World Sudoku Championship in Italy
Proof that 17 is the minimum number of clues
Sources and Further Reading
The historical facts in this article can be verified through the following sources:
- Felgenhauer, B. & Jarvis, F. (2006). "Mathematics of Sudoku I" โ Mathematical Spectrum
- McGuire, G., Tugemann, B., & Civario, G. (2012). "There is no 16-Clue Sudoku" โ arXiv:1201.0749
- World Puzzle Federation (www.worldpuzzle.org) โ Official championship records
- Nikoli Co., Ltd. (www.nikoli.co.jp) โ Original Japanese publisher
- The Times Digital Archive โ First UK Sudoku publication