A Brief History Of Sudoku

Although most people initially believe Sudoku originated in Japan this is, in fact, not quite the case. It is true that the Japanese certainly popularised the game and then exported it back to the West where it really took off, but it was an American who invented the game back in 1979. Published by Dell Magazines and created by Howard Garnes under the name of "Number Place" as it is still refered to by many Japanese publishers (or Napure for short) it didn't make it to Japan until 1986 when Nikoli published it in one of their own puzzle magazines under the more familiar name of Sudoku - an abbreviation of "Suji wa dokushin ni kagiru" - which literally translates as "the digits must occur only once" which is ultimately the rules of Sudoku.

How To Play Sudoku

The rules of sudoku are actually very simple:

You are presented with a 9x9 grid, subdivided up into 9 regions of 9 squares each for a total of 81 squares. Initially, some numbers are filled in, the rest it is up to you to discover using basic logic and following three simple rules:

1. Every column of 9 squares must contain the numbers 1,2,3,4,5,6,7,8,9 with no duplicates.

2. Every row of 9 squares must also contain the numbers 1 through 9 with no duplicates.

3. Every 3x3 region must also only contain the numbers 1 through 9 and again, with no duplicates.

Following the rules exactly as above, a correctly formed sudoku puzzle should have only one solution.

Despite the use of numbers in a traditional sudoku puzzle, it is not necessary to use numbers at all and any unique set of 9 symbols can be used instead. There is no mathematical ability needed to play sudoku and many of the variant puzzles out there use letters or other symbols in the formation of their puzzle grids.

Sudoku Variations

The popularity of sudoku has lead to several variations on this addictive puzzle game with new ones cropping up all the time. There is a huge sudoku fanbase online which leads to innovative variant sudokus which include some of the following:

Samurai Sudoku - A Samurai Sudoku is also known as a Gattai 5 puzzle and is basically a set of 5 overlapping sudoku puzzles arranged in the shape of an X. In order to complete a samurai sudoku puzzle you need to basically treat each sudoku grid as a separate entity but keep in mind, the places where the puzzles overlap must satisfy the conditions for both those puzzles in order to be correct. There are numerous places where you can find samuri sudoku puzzles, solutions and solvers for free online.

Wordoku - Also known as letter sudoku or alphabet sudoku this puzzle basically replaces the idea of using numbers for sudoku and instead uses the English alphabet instead. Wordoku puzzles usually have a hidden word along the diagonal which adds a little extra dimension to the puzzle so when completed, the letters spell out a hidden word if you have solved it correctly.

Codoku - Codedoku, Code-doku and other name variations all apply the another type of sudoku puzzle in which there is a hidden message coded in some way into the puzzle. Some sites keep this message on a theme such as quotes from famous novels etc. but all feature a coded word in the puzzle grid which is only revealed upon completion of the puzzle.

Killer Sudoku - Whereas a normal sudoku puzzle involves no mathematical ability at all on the part of the player, the Killer Sudoku style of puzzle requires simple addition skills in order to play. These are generally more challenging puzzles and are basically a cross between Sudoku and Kakuro (a.k.a. cross-sums). Further variants on this theme includes Killer Samurai Sudoku and 'killer' just about any of the other variant puzzles out there.

More Sudoku Variants? - Try a search on your favourite search engine for "sudoku variations" or similar.