The world celebrates September 9 International Sudoku Day. The holiday was started in 2012 by the World Puzzle Sports Federation (WJPF). WJPF is an association of legal entities from different countries of the world. The playing field of the sudoku puzzle consists of 9×9 cells – that’s why the ninth day of the ninth month was chosen.

The roots of this now popular game go back to Ancient China, where the so-called magic squares were known. In Europe, the first image of a puzzle appeared in the 18th century. in the form of the game “Latin squares”, which was invented by the blind Swiss mathematician Leonard Euler.

Sudoku in its modern form first appeared in 1979 in an American puzzle magazine. The author of the game was the architect Howard Garns. In 1984, the game appeared in Japan, where it was given the name “Sudoku”. This word is an abbreviation of an expression that translates from Japanese as “numbers limited to one location.” In Japan, the puzzle immediately became popular, because the Japanese language is not suitable for solving crossword puzzles.

In 1997, a judge from New Zealand, Gwain Gould, saw Sudoku in a bookstore in Tokyo and was fascinated by the puzzle. Gould spent six years creating a Sudoku computer program. In this way, he brought the puzzle back to the Western world.