Sudoku is the widely known puzzle that improves your memory, stimulates your mind, learns to do things quickly, increases your concentration power and makes you happier when a solution is found!
The name Sudoku or more correctly 数独 comes from Japan and consists of the Japanese characters Su (meaning ‘number’) and Doku (meaning ‘single’) but it was not invented in Japan.
The idea of Sudoku puzzles expands the principle of the magic square. This is a square grid n x n filled with distinct positive integers in the range 1 .. n^2 such that each cell contains a different integer and the sum of the integers in each row, column and diagonal is equal.
The Magic square is first documented in China about 7 century BC. As the story goes, an ancient Chinese masters derived the wisdom of the magic square from the patterns on the back of the turtle. By reading those patterns they saw a hidden natural rhythms or laws of the Universe.
There are several slightly different stories about different masters. So, the more popular legend is about the Emperor Yu walking along the river Lo. The turtle that emerged from the river had an unusual 3×3 pattern on its shell. So later it became the basis of the Lo Shu Square (meaning the Scroll of River Lo). It is a grid 3×3 where the sum of numbers from each row, column or diagonal is 15.
The magic square reached Europe from China by way of the Arabs who brought news of many of the Chinese inventions with them along the Silk Road. Thabit ibn Qurrah (9 century AD) is credited with introducing the magic square to the Western World.
In Europe the first unequivocal appearance of the square is in Albrecht Dürer’s engraving called ‘Melancholia’ in 1514. It where a 4×4 magic square is clearly shown with an arrangement of the first 16 numbers. They gives a sum of 34 in all rows, columns and both diagonals. Two numbers in the center of the bottom row indicates a date of the engraving (15 and 14).
In 18 century a Swiss mathematician Leonhard Euler developed the basics of ‘Sudoku’ which he termed Graeco-Roman Squares or Latin Squares. He used letters as the grid square symbols rather than numbers. The first four letters of the Greek alphabet α, β, γ, δ are combined with Latin alphabet a, b, c, d so that each occurs once in each row and column.
Puzzles with the modern rules was first published in Dell Puzzle Magazines, New York in 1979. The puzzle’s author Howard Garnes called it Number Place. New interesting puzzles traveled to Japan soon. In April 1984 it was first printed in Monthly Nikolist magazine. So, it became a very popular pastime. The American name Number Place was translated as “Suuji wa dokushin ni kagiru Suuji wa dokushin ni kagiru” meaning “the numbers must occur once only”. As a result, it quickly became abbreviated to 数独 or Su Doku.