International Sudoku Day, an annual Sept. 9 celebration of the logic-based puzzle, was founded in 2013 by the World Puzzle Federation in 2013.
The holiday was first celebrated in 2013 by the World Puzzle Federation, described as “an association of legal bodies with an interest in puzzles,” and the date Sept. 9, often stylized as 9/9, was chosen in honor of the 9×9 grid that makes up a sudoku puzzle.
While many grid-based number games existed in the past, the modern version of sudoku is believed to have been invented by Indiana man Howard Garns, who submitted his puzzles n the 1970s and 80s to Dell Magazines under the name “Number Place.”
The game was given the the name sudoku when it was introduced in Japan in the 1980s, and it kept the name when Wayne Gould, a Hong Kong judge, convinced The Times of London to start publishing the puzzles in 1997.
Other holidays and observances for Sept. 9, 2022, include Care Bears Share Your Care Day, Fetal Alcohol Spectrum Disorders Day, International Buy a Priest a Beer Day, National Dog Walker Appreciation Day, National Steak Au Poivre Day, National Teddy Bear Day, Stand Up to Cancer Day, Testers Day, Wienerschnitzel Day and Wonderful Weirdoes Day.