Sudoku: Over 150 Puzzles Easy to Very Hard - Enigmista Mastery

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Résumé :
HISTORY OF THE SUDOKU GAME
Sudoku was called the Rubik's Cube of the 21st century. It is a puzzle based on logic and numbers, but to solve it it is not necessary to be a mathematical genius, but only logical reasoning and a lot of patience.
It is commonly said that the game was born in Japan in 1984, but in reality Sudoku finds its origins in the so-called Latin squares imagined by the Swiss mathematician Euler in the 18th century.


The origins: Latin squares each row and in each column each symbol must appear once and only once.


EVOLUTION: NUMBER PLACE


In the late seventies, in the magazine Math Puzzles and Logic Problems, the publishing house Dell of New York proposed Number Place, a puzzle based on the rules of composition of Latin squares. The aim of the game was to fill with the digits from 1 to 9 only a 9 x 9 square grid, divided into nine 3 x 3 subschemes, starting from some numbers already placed and making sure that in each row, column and sub-grid each digit appeared once and only once.


Finally Sudoku!


This puzzle-game arrives in Japan in the mid-eighties: in 1984 it is proposed in the magazine Monthly Nikolist of the company Nikoli , under the name Sunji wa dokushin ni kagiru . The name was soon shortened to Sudoku , where su stands for number and doku for single.


In 1986 Nikoli introduced two changes
-the numbers provided to start the game must be no more than 30.
Since then this puzzle has spread throughout Japan, becoming extremely popular. Sudoku arrived in Europe only in 2004, thanks to Wayne Gould, a retired New Zealand judge, who discovered the puzzle in Tokyo in 1997 and became the most famous Sudoku scheme maker.
In 2004 Gould proposes this game to the London newspaper The Times, which publishes the first play on November 12. The example was immediately followed by other newspapers and, since then, the game spread throughout England, until the boom that reached the rest of the world.
Explanation of the SudokuPurpose of the game complete the classic scheme so that each column, each row and each block contains all in numbers from 1 to 9, none excluded and without repetitions. Some numbers are already contained in the scheme, so that the solution is addressed. The more numbers inserted in the scheme, the faster it becomes to reach the final solution.




HOW TO PLAY SUDOKU


Sudoku a solitary game of logic in which the player is proposed a grid of 9 9 cells, each of which may contain a number from 1 to 9 or be empty or white; the grid should be considered divided into 9 sub-grids, called regions, of 3 3 contiguous cells. The player is proposed a grid in which only some cells, from 20 to 35, contain numbers. The aim of the game is to fill the empty spaces of a grid made of rows, columns and squares with numbers from 1 to 9, so that each row, column and region contains all the digits from 1 to 9.


Manual puzzle Sudoku must meet three requirements initial numbers should be less than 35.
It is worth pointing out that, contrary to what is often said, sudoku is a game of logic but not really mathematics, let alone the game has to do with numbers. The properties of numbers are never used, nor is the fact that they are numbers ever used.