Sunday, September 24, 2017

Sudoku DIY

Is that a thing? Well, if you don't know how to play Sudoku (soo-doh'-koo), I'm happy to explain. I am an addict. A few times I've put the app on my phone but I always remove it because I just get sucked in.

Here goes.
 This is the weekly puzzle from the newspaper. They rate this one as "Challenging". I think it's pretty easy.
 I mostly play by the elimination process. There is supposed to be a 5 in every row, every column and every 9-box square as you can see if you can read the directions on the paper. I usually start with 1 and see if I can find a place where I KNOW a 1 will go. If I am not 100 percent positive, I won't put it in. So I've gone through 1, 2, 3, and 4, and now 5 is the first number that I've found four spots for.
 By looking across the puzzle you can see that certain rows and columns have 6's in them so you know you can't put another 6 in that row or column. Take, for example, the second 9-square box down on the left. Look in the 9-square boxes above and below and you will see a 6 in each. In the second row and the third row. So that leaves only two squares on the left in this 9-square where 6 can be a possibility. Look to the right and the 9-square beside this one has a 6 in it, in the second row down. That leaves the top left square as the only possible place for a 6 to be.
 Now I found a space for one 8. There are only two other 8's in the whole puzzle right now and this is the only spot that is absolutely the right space for another 8. At this point I can find no other sure spaces for the number 8.
 So I started over with 1, found no places I could be sure of, but found a few spots now where 2's belong.
 And one 3.
 Now I'm pointing out that I've found a row that has only two spots left to fill. We know that 3 and 4 have to go in this row yet.You can see in the space my pen is on that there is a 3 in that column. That lets us know that 3 belongs in the last space of this row and 4 will be in the square my pen rests in. 

You see the 5 and 6 I've penned on the bottom of the sheet. I'm just making a note to self that these numbers are completed.
 Here is another place, a 9-square, where there are only two spots left to fill. 1 and 9 go in these places but because I can't be sure which squares they go in, I'll leave it and go somewhere else. I like to see if there are places where only a few numbers are needed to complete a row, column or square. Sometimes it is easily completed and other times, like this, it must wait. 
 Oh, but this 9-square is simple to complete. It needs a 1 and a 4. As you can see there is a 4 in the column to the left of the one my pen rests in so the spot I'm touching will hold the 4.
 9 and 3 are needed to complete this 9-square. (You count from 1-9 a lot as you play this game.) Since there is a 3 already in the row above my pen I will put a 3 where my pen rests and that automatically means 9 goes in the space that's left. 

But then if I would have been more observant I could have saved myself some headache. There is only one space left in that row right above my pen. Simple.
 Now here's an interesting one. The spot my pen rests in will be a spot for 1. How do I know? In the 9-square below this one I've determined that one will not be in the first column to the left because that column holds a 1. As I look to the right I see that 1 cannot be in the middle square as it is already in that row. That means 1 will need to be in one of the two spots in the column on the right in that bottom 9-square. Since it will be in that column it cannot be in the square to the right of my pen. That leaves only the spot where my pen is for 1. That is a little more 3 dimensional thinking maybe.
 What number will go at this spot? 9. How do I know? Look across this row. Only three spots left to fill and if you look at the other two columns they have 9's in them already.
Completed puzzle
Was that as clear as muddy water?

Could you explain it better?

Have you gotten hooked?

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