The roots

The seeds that gave way to our current and beloved Sudoku over the centuries are born from the concepts of Latin Square and Magic Square. The name of Latin Square results from the use of the Latin alphabet to fill a matrix or a square, while the Magic Square refers to the positioning of digits in a table according to a mathematical formula so that the sum of each line and column is always the same.

Already in medieval Islamic culture (1,200 AD) various amulets appear following the concepts of both the Magic Square and the Latin one. But it will not be until centuries later, in Korea, that the first literary treatise dedicated to the Latin Square will be published: “Koo Soo Ryak” by the hand of the politician and mathematician Choi Seok Jeong (1646-1715). Unfortunately, the figure of Seok Jeong is mostly overshadowed by that of the Swiss physicist and mathematician Leonhard Euler (1707-1783).

Euler was trying to create a mathematical system of statistical analysis and, to create it, he combined the concepts of the Latin Square and those of the Magic Square. Euler showed his results in the scientific study “De quadratis magicis” that he presented at the Saint Petersburg Academy of Sciences in 1776, where he applied various restrictions on tables of 9, 16, 25 and up to 36 cells, showing how to create magic squares with the Latin alphabet.

The log

After waiting a few more years, about 200 or so, we come to 1979. While China introduces its One-child Policy and Margaret Tatcher is elected Prime Minister of the United Kingdom, the American magazine Dell Pencil Puzzles and Word Games publishes what is considered the first modern sudoku game.

The number puzzle appeared under the heading “Number Place” and the players had to place the numbers from 1 to 9 in a 9×9 table, without repeating the digits in a line or column. Although he was never officially credited, it is believed that it was Howard Garns, then a retired Indianapolis architect and puzzle fan, who devised this puzzle.

“Number Place” quickly became one of the most popular puzzles in Dell publications, but its refinement and worldwide expansion would now come from Japanese hands.

The flowering

Five more years have passed and Monthly Nikolist Magazine publishes a puzzle titled “数字 は 独身 に 限 る / “Suuji wa dokushin ni kaguru” (Numbers must stand alone).

These puzzles followed the same principles as the American ones, but introducing two new rules:

1) The numbers assigned at the start of each game should create different layouts.

2) The puzzles could not be started with more than 32 assigned numbers of the total of 81 that make up the table. This ensured that the game was always challenging, even on the easiest levels.

These puzzles were a great success in Japan and were quickly adopted and published by other publications. Due to its popularity, its name was eventually shortened to include only the characters representing number ((数 – Su) and only (独 – Doku), that is, Sudoku.

Seed expansion

A decade later, in 1997, another retiree who was fond of puzzles would help the worldwide expansion of Sudoku. Wayne Gould, a retired New Zealand criminal court judge in Hong Kong discovered a Sudoku book on a vacation to Japan and became intensely hook by it.

Over the next 6 years, Gould created a computer program that allowed him to generate Sudoku tables and determine their level of difficulty automatically. Once he had perfected it, taking advantage of the fact that his wife Gaye was a Linguistics teacher in New Hampshire (USA), in 2004 he convinced the editors of the local newspaper Conway Daily Sun to publish some of his puzzles. The success was resounding. Then, going back to Hong Kong and taking advantage of a stopover in London, he went to the offices of the famous newspaper The Times without an appointment and convinced them to publish his puzzles. And from there, the rest is almost history. Quickly, many western publications joined the publication of Sudokus and its worldwide fame was a reality.

Such was the unexpected fame that Wayne Goud ended up on the list of the 100 most influential personalities of the North American magazine Time in 2006, thanks to his role in the popularization of Sudoku puzzles.

2006 was also the year that hosted the first Sudoku World Championship in Italy, an annual event in which individual players and national teams participate to solve puzzles of different difficulty levels in the shortest time possible.

Take a look at our own Sudoku books!