Sudoku doesn't require any special math skills or calculations. It is a simple and fun game of logic -- all that's needed is brains and concentration.

There is really only one rule to Sudoku: Fill in the game board so that the numbers 1 through 9 occur exactly once in each row, column, and 3x3 box. The numbers can appear in any order and diagonals are not considered. Your initial game board will consist of several numbers that are already placed. Those numbers cannot be changed. Your goal is to fill in the empty squares following the simple rule above.

Many of the games available on Sudoku.com feature unique twists on Sudoku basics. Experiment with the different Sudoku games and discover these exciting variations!

According to Will Shortz, the modern Sudoku was most likely designed anonymously by Howard Garns, a 74-year-old retired architect and freelance puzzle constructor from Indiana, and first published in 1979 by Dell Magazines as Number Place (the earliest known examples of modern Sudoku). Garns's name was always present on the list of contributors in issues of Dell Pencil Puzzles and Word Games that included Number Place, and was always absent from issues that did not. He died in 1989 before getting a chance to see his creation as a worldwide phenomenon. It is unclear if Garns was familiar with any of the French newspapers listed above.

The puzzle was introduced in Japan by Nikoli in the paper Monthly Nikolist in April 1984 as Suuji (or suji) wa dokushin ni kagiru, which can be translated as "the digits must be single" or "the digits are limited to one occurrence." At a later date, the name was abbreviated to Sudoku by Maki Kaji, taking only the first kanji of compound words to form a shorter version. In 1986, Nikoli introduced two innovations: the number of givens was restricted to no more than 32, and puzzles became "symmetrical" (meaning the givens were distributed in rotationally symmetric cells). It is now published in mainstream Japanese periodicals, such as the Asahi Shimbun.