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Sunday, July 29, 2012

How to Solve Sudoku Puzzles

Y u no love Japan?!?!
   
        "Why the (insert swear word here) would I want to do a Sudoku puzzle?" Well, I can't force you to try one out, but virtually everyone I've introduced a Sudoku to said that it was easier and more rewarding than they thought. Yes, I promise, no math! Give it a try, and if you don't feel that sense of accomplishment when you complete one (and yes, you *will* succeed), then sue me.

I repeat, no math!

Your life goal.
What are the rules?

  • The numbers 1-9 (including 1 and 9) must all be present in a row, no repeats
  • 1-9 must also be in every column, no repeats, no exceptions
  • 1-9 must ALSO be in the nine 3x3 boxes, no repeats, no exceptions!
  • That's about it.
        If that sounds next to impossible, or somehow reminds you of the matrix, let me reassure you that it's easier than you think. Ready?

     
     
How to Succeed:


         1. Pick out your enemy. Size him up. If it's your first Sudoku, I recommend a beginner or easy puzzle.

You're going down, Websudoku.com.
        2. Use the rules of the game to win the game. What do I mean? Well, if you remember, a number cannot appear more than once in any row or column, so we can use this to imagine lines where 3's cannot go. Like so.
Using the 3's "line of sight" to see where that gets us.

        3. If we look at the box in the center, we can see that it is lacking a three, and that there is only one place for that 3 to go. So, we've solved that box! Go ahead and fill that in, and enjoy a little rush of dopamine.
1 down, 42* to go.
        4. Try that strategy with whatever numbers you like. On the easiest of puzzles, that should be enough. After going through a full cycle of all the numbers, you might want to check for newly forced boxes.
4's, yo.
Using the newly discovered 4's in a chain reaction.
          5. Looking at this situation right here, we can see that in the third row there is only one number missing. After quick analysis, it becomes apparent that the only number missing is 9. So put the nine where it belongs and dance a jig, dingus.
Mad skills.
        6. We didn't forget the rule about 3x3 boxes, did we? If you recall, boxes must also follow the 1-9 rule. Since we found a 9 for the box in the top left corner already, none of the other squares in that box can have a 9. So we can combine our box rule here with our "missing number" strategy from step five, and conveniently place a different nine on the board.
Ooh, purple!
       6.5. Then, we can go back and finish off the column with ease!
          7. I promise, you'll pick up speed as you do more boxes, and after a while you'll be solving these puzzles like this:

Rain Man speeds, it's how we do.
       And this:
Almost there...


         8. Fill in the last box with pride, and show everyone in the immediate vicinity your accomplishment! Then, sit back and remark on your logic abilities, and see if you can do another one more quickly.

Brain training games? Pssht, I do Japanese logic brain training.
         
          You may get stuck at points, where finding the next number might take a long while. It happens, just make sure you try different strategies, and look through every possible outcome. If you're looking for more advanced strategy for more difficult puzzles, check out this article.
             
         




                                                                                                 P.S. - The last number was an 8!