Sudoku is a logic-based number placement puzzle consisting of a 9×9 grid divided into nine 3×3 squares. The objective is to fill the grid with numbers 1-9, each appearing once in each row, column, and square. Sudoku gained worldwide popularity in 2005 and can be played in various forms. The concept can be applied to other objects, and the degree of difficulty is based on the placement of data. The modern version was popularized in Japan in 1986 and patented by Nikoli. Its international popularity began in 2004, and the first championship was held in Italy in 2006.
Sudoku is a number placement puzzle based on logic rather than mathematics. Sudoku gained worldwide popularity in early 2005 and began selling in the form of puzzle books, portable electronic versions, and board games, as well as appearing in thousands of newspapers.
The concept of Sudoku is simple. The puzzle consists of a 9×9 square grid that is divided into nine 3×3 squares, resulting in nine rows and nine columns, for a total of 81 small squares. Sudoku unsolved puzzle provides only few numbers in random squares. To solve the puzzle, the remaining squares must be filled with the numbers 1 to 9, each appearing only once in each row, column and 3×3 square.
Since Sudoku is based on logic, other puzzles could be created that use the same concept and replace the numbers with other objects, such as colors, letters or shapes. However, Sudoku is aptly named, because the word Sudoku is a Japanese abbreviation that loosely means “single number.”
At its most basic, Sudoku comes in the traditional 9×9 square grid with varying levels of difficulty. The degree of difficulty to solve the puzzle is not based on the number of squares with numbers provided, but rather on their placement on the grid. These supplied numbers are called data. The complexity involved in solving the puzzles varies so that anyone can enjoy a Sudoku puzzle that parallels their skill level. There are some variations of the puzzle where the grid is changed to fit more squares or more restrictions are placed on the placement of numbers.
While this puzzle concept has been around for years under many different names, the modern version was popularized in Japan in 1986 when puzzle publisher Nikoli discovered a puzzle originally published in Dell Magazines as “Number Place.” Nikoli patented the word Sudoku and started publishing the puzzles in various difficulty levels, which became very popular in Japan. In 2004, Sudoku’s international popularity began when a puzzle was published in a British newspaper as a result of a computer program developed by Wayne Gould that could rapidly generate the puzzles. From there, the puzzles’ popularity eventually spread across the United States and elsewhere. The first Sudoku championship took place in March 2006 in Lucca, Italy.