Sudoku refers to a puzzle consisting of a 9-by-9 grid of squares, each divided into nine 3-by-3 squares. Some of the squares already contain a number. The aim is to fill in the remainder so that every horizontal and vertical line, and every 3-by-3 square, contains the numerals 1 to 9 with no repeats.
The puzzle first appeared in the USA in the early 1980s under the name Number Place and was taken up by the Japanese publishing house Nikoli in 1984. Its current Japanese name is formed from the original title at that time, which may be translated as “only single numbers allowed”. The short form is a compound of the Japanese words su and doku, which respectively mean “single” and “number”.
It has recently become a widespread and addictive craze here in the UK (the derived term sudokumania has been coined for it). It has now returned to the USA and has also become common in other countries.
The first puzzles were featured in The Times back in November 2004 and soon after in the Daily Mail and several other newspapers, though the craze really took off around May 2005. The Mail’s puzzles are comparatively easy, I’m told, with 32 of the 81 squares already filled in. Others have fewer and are correspondingly harder.
There is no adding up, subtraction, multiplication or division in Sudoku. You do not even need to know that two plus two equals four. But, boy, can it make your brain ache, your pulse race and knuckles whiten as you grip your pen in exasperation or, finally, ecstasy!
the Daily Mail, 12 May 2005
And filling the committees is a complex task, like trying to complete 30 inter-related Sudoku puzzles simultaneously.
the Independent, 22 Jul. 2005