## How play

### What's Sudoku?

From a time to this part, a game is causing rage. Puzzle of numbers. The English press has gotten it to baptize like the Rubik Bucket of century XXI. Crucigramas, soups of letters..., are being replaced by a new game of North American although popularized origin in Japan.

The SuDoKu is a mathematical puzzle of which it began to speak in 1986 and it occurred to know internationally in 2005. 3x3. has the aspect of a grill of crucigrama of 9x9 with its 81 littles squares grouped in nine inner squares of dimensions. Any number in a same row, column or subgrid are not due to repeat. A SuDoKu well is raised if the solution is unique.

Of some form the Sudoku is based on the search of the perfect numerical combination. There are different levels from difficulty and the resolution of the problem requires patience and certain dowries logics. Professors worldwide recommend like method to develop it the logical reasoning.

In fact, it is not obligatory to use numbers, but that also letters, forms or colors without altering the rules can be used, but numbers by convenience are used. Although the grid commonest is the one of 9×9 with regions of 3×3, also are used other sizes.

In addition, the regions do not have why to be square, although they are it generally. It is very easy to explain and that is what it makes popular tremendously. In fact already the pages are hundreds Web that contain information on like solving them.

Text extract from a work of Sanz Atienza Esnoz.

### History

More surely it is than the SuDoKu was created from the works of Leonhard Euler (1707-1783), famous Swiss mathematician. This it would not have created the game in himself, but that would set the standards for the calculation of probabilities.

Some sources indicate that the origin of the game can be located in New York (the U.S.A.) at the end of years 1970. Then SuDoKu but Number Place was not called simply (the place of the numbers), being published in the magazine Math Puzzles and Logic Problems (mathematical Puzzles and logical problems) of the company specialized in Dell puzzle. The name is not known the designer of first puzzle of this type, although surely he was Walter Mackey, one of the designers of puzzles of Dell.

Later Nikoli, specialized Japanese company in pastimes for press, exported it to Japan publishing it in the newspaper Monthly Nikolist in April of 1984 under the title "Suji wa dokushin nor kagiru", that can be translated as "the numbers must be single" (literally "celibate, unmarried"). It was Kaji Maki, president of Nikoli, that put the name to him. The name was brief to Sudoku (his = number, doku = single); since he is practical common in Japanese taking first kanji (characters used in the Japanese spelling) from composed words to be brief them. In 1986, Nikoli introduced two innovations that would guarantee the popularity of the puzzle: the number of numbers that came given would be restricted to a maximum of 30 and puzzles would be "symmetrical" (that is to say, the cells with given numbers would be had symmetrical form).

After small variations until giving with the formula that today is so popular, the SuDoKu extended by the Japanese press and began its jump to the rest of the world.

The first computerized version was registered in 1989, by work of Loadstar Softdisk Publishing, with the name of DigitHunt, published in Commodore 64, in which it seems the first version for computer.

In 1997, Wayne Gould, judge of the Court of Hong Kong. During vacations in the Japanese country, it found a magazine of Sudoku, game that an enormous acceptance between the Japanese citizens had. This it is the principle of the arrival from the Sudoku to Europe. The supply of publication arrived to him at The Times, in London, that published the first pastime the 12 of November of 2004. Three days later, The Daily Mail copied the game and after him the practical totality of the British press.

Another company of pastimes, Kappa, reprinted, the SuDoKu de Nikoli in Games Magazine with the name Squared Away. At the moment several North American newspapers of national distance publish puzzle in their pages. Even the original company, Dell, publish 2 specialized magazines: Original Sudoku and Extreme Sudoku.

What is clear is that 2005 are the year of the Sudoku. In summer it arrived at the television. The first emission was made by the channel Sky British One. Nine equipment with nine players each one. The viewers also could participate, of interactive form. Nevertheless the program was not the waited for successful, putting in evidence the difficulty to adapt this pastime to a televising emission.

What if were obtained it was to make the SuDoKu greatest of the world, in a hill near Bristol., with 84 meters in length.

Extraicto text of work of Sanz Atienza Esnoz.

### Basicas slight knowledge

Suduku, Soduku, Sodoku, Sodoko, his doku, songoku, Sudok. Enigmas, game, puzzle, puzzles, games... people give many names him. Sudoku is a mathematical puzzle of positioning that became popular in Japan in 1986 and it occurred to know in the international scope in 2005. The objective is to fill up a grid of 9×9 cells divided in subgrids of 3×3 of the numbers from the 1 to the 9 starting off of some numbers already had in some the cells. Any number in a same row, column or subgrid are not due to repeat. The resolution of the problem requires patience and certain dowries logics. You dare?

### Like solving them

Next are some advice of resolution summarized in blog Microsiervos:

Advice to solve Sudokus (1)

Advice to solve Sudokus (2)

Advice to solve Sudokus (3)

Advice to solve Sudokus (4)

Advice to solve Sudokus (5)

Advice to solve Sudokus (6)

### Tricks

** Before beginning **

- Asegúrate of which you have good sudoku ahead that it knows to you to challenge, either in paper or online. Next déjanos darte some basic advice who will do the life once to you a little simpler you have entered the world sudoku.

** Look to the percal **

- It looks for the rows and columns with "given" numbers. Followed, you have to determine which are the numbers that lack in these spaces. Once this you have it controlled, for example, in a row in particular, you can happen to scan the columns that intercross with the empty cells and to see thus what numbers are those that exceed.

Also, you can throw a look to the numbers within the regions of 3 Xs 3 and see if some numbers can be eliminated.

** Marking the territory **

- If once done the previous thing, you have left to a pair of possible numbers in a cell, escribelos upon the cell and returns on them once who you have completed more numbers.

** Reasonable riddles **

- the logical one is the only safe medicine that it will take to you almost until the borders of sudoku. Nevertheless, some moment the science of the reasonable riddle enters game. Once you have filled up the most possible board (following the 2 first advice) usually they arise ideas on what possible numbers can fit in the empty cells.

It continues completing the cells that lack with a possible number and at this moment it is begun to look for the solution until the end of puzzle. At some given moment (if everything has gone or) descubriras if the application of your reasonable riddles has been correct (OR DONE) or if on the contrary nothing finishes fitting and you have put the leg. In any case they ten well-taken care of then in some ocaciones is only towards the end when descubriras that you need to return to begin again.

Trick, but tricks and ideas gone away of e-sudoku.com