# The story of Sudoku

Sudoku is a game played in a 9×9 grid. The grid (or board) consists of 9 smaller, 3×3 boards. When you start the game, the grid already contains some digits from 1 to 9 scattered all over the board. The empty squares must be filled by the player with digits from 1 to 9 in a way that each row, column and 3×3 subgrid contains each digit from 1 to 9 only once. The concept of the game comes from the 18th century Swiss mathematician, Leonhard Euler. He invented what we call today a ‘Latin square’: in a n×n Latin square each one of the digits (1, 2, …, n) appears only once in each row and in each column. The name of the game comes from the fact that in the beginning Euler used the letters of the Latin alphabet instead of numbers. The predecessor of Sudoku first appeared in a French newspaper in 1892. By that time, the 9×9 board has already been divided into 3×3 subgrids. It still contained multi-digit numbers and the players had to follow different rules when filling in the squares. The present form of the game, that we all know and play today was invented in 1979 by an American architect, Howard Garns. The game arrived in Japan in 1984, where it first appeared in a magazine called Nikoli as a puzzle to be solved. The name Sudoku, that we all know today, comes from its old name used in Japan at that time: ‘Suuji wa dokushin ni kagiru” which means that each digit can only appear once.

## The detailed story of Sudoku

Sudoku is a Japanese word, but it doesn’t mean that the game comes from the Asian country. The basis of the game is a theory created by a Swiss mathematician, Leonhard Euler in 1783. His theory was that you have to fill a row or a column with digits in such a way that each row and column must contain each digit only once. He created the ‘magic square’ using Greek numbers or the letters of the Latin alphabet, that’s why for a long period of time the puzzle game was called ‘Greek’ or ‘Latin square’.

Its first appearance to the general public happened in 1892 in Paris. On November 19, 1892, the Le Siècle newspaper published a partially completed 9×9 magic square with 3×3 subgrids. This however cannot be considered a real Sudoku as it also contained double-digit numbers and the puzzle had to be solved using arithmetics rather than logic. However the main characteristics were the same: in every row, column and subgrid the sum of the digits were the same. On July 6, 1895, a rival of Le Siècle, La France perfected the game and the result was almost like the modern version of Sudoku. They simplified the 9×9 magic square puzzle so that every row and column contained the digits from 1 to 9, however they didn’t mark the subgrids. Even though the subgrids weren’t marked, every digit could only be used once in each one. In that version the key to solving the puzzle was the broken diagonal. For over a decade, these weekly puzzles often appeared in French newspapers such as L’Echo de Paris, but during World War I, they became forgotten.

The modern Sudoku was invented by Howard Garns, a 74 year old retired American architect and freelance puzzle constructor from Indiana. It was first published in the Dell magazine in 1979 under the name ‘Number Place’. Garns passed away in 1989, so he could not live to see his invention become recognized and popular all over the world. The game extended with Howard Garns’ supplementary rules was published for the first time in 1979. His puzzle was published by Dell Magazine which has been publishing crosswords for over 50 years. Garns surprised the public with a 9×9 grid divided into smaller, 3×3 subgrids or tables. The game at that time was called ‘Number Place’. At that time it only enjoyed moderate success.