It is difficult to think of a puzzle that became a worldwide sensation quite as immediately as Sodoku, but to explain why this happened, it is worth exploring what the name means and where it comes from.

The name “Sudoku” is a condensed version of the Japanese phrase “Suji wa dokushin ni kagiru” (数字は独身に限る), which roughly translates to “the numbers must be single”.

This name has created the myth that the puzzle is Japanese, but whilst this is not the case, its popularity can be credited to the particular puzzle philosophy of one of Japan’s biggest puzzle publishers.

In Japan, where Sudoku is a registered trademark, the puzzle is known as Number Place or “Nanpure”, which was also the name used by the original designer of the puzzle, Howard Garns of Indiana.

After being first published in the United States as Number Place, Maki Kaji of Nikoli, one of Japan’s biggest puzzlemakers, published the puzzle in 1984 under the Sudoku name.

Nikoli was famous for its preference for “culture independent” puzzles, a philosophy that tried to minimise the amount of outside knowledge you needed to solve a puzzle outside of the rules the game gave you.

Many of their puzzles, therefore, involved numerical grids, mazes and shapes, all of which could be solved by anyone without needing to know anything other than the rules and an assumption that the puzzles would use the numbers 1-9.

The reasoning for this, according to Nikoli themselves, was to reward players who had an open mind without causing unnecessary stress by adding questions they simply did not know.

A crossword puzzle, for example, often relies on extensive outside knowledge to solve, but Sudoku can be solved by anyone with the time and determination to figure it out.

This is part of the reason why Sudoku became so popular outside of Japan so quickly; anyone of any age can try it, and all they need to know is that the numbers one to nine need to fit somewhere.