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## Sudoku

Published on Sunday, January 15, 2006 in , , ,

Suuji wa dokushin ni kagiru!

Loosely translated from the Japanse, this means, "Each number remains single." Thankfully, this phrase has been shortened in one simple word: "Sudoku."

Anyone who knows me, even those of you just know me just from this blog, had to realize that it wouldn't be long before I became addicted to Sudoku.

Even though it's becoming the hottest thing to hit the puzzle world since the Rubik's Cube, I'll go over the basics for the one or two people that haven't heard of it yet. Sudoku is a puzzle played (usually) on a 9 by 9 grid, which contains nine 3 by 3 smaller squares within. As in the picture above, a puzzle will have some numbers already filled in. The object is to fill in all the empty boxes, so that each row, column and 3 by 3 box contain each of the numbers 1 through 9 once, and only once. If you're not clear, this visual explanation of Sudoku rules will be of some help.

Despite the numbers, Sudoku really isn't a mathematical puzzle. Rather, it is a logical one. Instead of numbers, you could replace them with letters, symbols or just about anything else, and the rules and strategies wouldn't change.

Figuring out which one of the various strategies you need, and exactly how it will apply is what makes Sudoku so fascinating and challenging.

There are only two strategies that allow you to deduce a single number, "Naked Singles" and "Hidden Singles".

However, just using these strategies alone may not help solve a Sudoku puzzle. Often, you'll need other techniques to help. These other strategies help reduce the number of candidates for each square. The more strategies you know, and the more advanced they are, the more difficult the Sudoku grid you can solve.

The toughest ones are the ones that require guesses, with some trial-and-error involved. For now, I suggest starting with the simpler Soduko puzzles, and familiarizing yourself with a solid, basic approach (PDF).

Fortunately, there's no shortage of puzzles. You can find them online, in books, on your OS X, Linux or Windows computer, and even in your shirt pocket!

By the way, if you're wondering...yes, theat one in the upper left corner is a real Sudoku puzzle, and it is solvable.