It's a popular Japanese math game commonly found in newspapers and publications with related games (crosswords, etc.)

On online message boards, particularly 4chan's /v/, people mix the word for Japanese ritual suicide, "seppuku," with "sudoku." The typo has since spread and became adopted in a similar fashion to "pwn" in regards to "own."
"If you seriously gave EA your money for that piece of sh*t you should just commit sudoku."
by Synchronous Failure March 13, 2012
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Ancient Japanese form of ritualistic suicide when they are dishonored, most commonly by sword.
After his father-san saw the boy disgraced by being called a comedian, he was forced to commit sudoku.
by Wafflociraptor May 12, 2014
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A lad's holiday pre-lash up ritual of heading back to the hotel room whilst everyone is poolside for some "slapping of the ham" before a big night out.
B: "I feel like I got sunstroke lads. I'm just going back to the hotel room to play some Sudoku."

(walking into the hotel room)

D: "B, what're you doing?!"

B: "I'm playing Sudoku! I swear!"
by Pablo Cheeps September 11, 2011
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A Sudoku is a japanese math puzzle consisting of 9 3X3 squares, each with 9 smaller squares inside. Once completed, the sudoku must have the numbers from one to nine appear once in each row, coloum and 3X3 square.
I just finished my sudoku in 7 mins!!!
by Sierra P. K. July 24, 2005
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A puzzle invented by an American but popularized by the Japanese.

The puzzle consists of a 9x9 grid which is partitioned into nine 3x3 boxes. Typically, 20 to 25 of the 81 cells are pre-filled with one numerical digit. The objective is to fill the remaining cells such that each digit (1 through 9) is represented in every row, column and box.

Easy to moderate puzzles can be solved via simple elimination.

More difficult puzzles require some "what if" propositions to solve.

Solving Sudoku by hand is a routine diversion but writing a program to solve or create Sudoku puzzles is a more interesting challenge.
I got a Sudoku book for Christmas and wrote a program that could solve any of the puzzles in under a second.
by AbnormalBoy January 8, 2006
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It's a 9*9 matrix with 9 3*3 submatrices. Each submatrix must have 9 numbers from 1-9 with no repetitions. When one combines the 9 submatrices to get a 9*9 supermatrix, each row and column of the supermatrix must have 1, and only 1, instance of the numbers 1-9.
So one has 9 3*3 matrices, the numbers 1-9 inclusive with no repetitions for each 3*3 matrix. Then combine the 9 3*3 matrices so the supermatrix has numbers 1-9 in each row and each column without repetition..
So here's how you solve 'em.. 1) Go through each 3*3 submatrix, trying to find an obvious digit that fits, from 1-9.. Each time you find an obvious fit, one must go through the entire supermatrix of submatrices again, in the sequence 1-9. When you've exhausted the possibilities, it is time to guess.
2) Guess at one where a single digit must belong to one of 2 positions. Follow step 1, and if you run into an error, that guess was wrong, and the number must rest in the other position.
3) One can adopt another strategy.. For instance, if there are 4 digits possible for a space, say, 2,3,4,5... and in another submatrix space, there are only 2 possibilities, say, 2, 3.... then the probability of the 2 being in the space with only 2 choices is larger than the probability of the 2 being in the space with 4 choices...
4) Many times, the puzzle will be lacking in 1 or 2 numbers, with a lot of the other ones. This is meant to confuse you. Do not pay attention to the numbers which are missing and try to fill those in. Instead, when it comes time to guess, try to fill a row or column so that the row or column has lots of obvious fill-ins.
5) When you guess, keep track of the number of the guess, like, "OK, this is the first guess..." then, if you must "second-guess," and that guess is wrong, the first guess was wrong as well... this is why one guesses only when there there are only 2 possibilities...
6) I have guessed up to the 8th level, but, as I get better, it only takes me 3 or 4 levels... Ah, hell, just Google for a Sudoku solver !!! I'm sure a million have already been written !! Only takes a bit of linear algebra !! Thanks..
by Johnny Chingas January 27, 2007
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A Japense puzzle that can be solved through logic and reasoning. It is a 9x9 square broken up into 3x3 regions and each region, row, and column must all have 1-9 within them. A number cannot be repeated within a region, row, or column; or it will not work. There is usuly about 27 of the 81 numbers given to you to get you started. The abundancey of how many of each number and where those number are placed, creates the difficulty of the puzzle.
Sudoku is very, very, very addicting and challenging and also mentaly healthy, but not as healthy as sex!!!
by SudoMaster...da Woman! November 7, 2005
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