sudoku help, please.

Post the puzzle or solving technique that's causing you trouble and someone will help

sudoku help, please.

Postby sudoku_n00b » Thu Mar 02, 2006 3:49 am

i need help with this one. i know it isn't too hard, but, yeah. just need pointers.
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Postby TKiel » Thu Mar 02, 2006 4:12 am

This puzzle solves with nothing but singles. In box 3 (top right 3X3 box), look to see where a 2 can be placed, as only one cell in that box has that for a candidate. Then do the same for row 7, 8 and 9 (1 is the top row). Now do that for each number and you'll solve the puzzle.

On left-hand side of the homepage of this website there is a menu of links. Click on the one called 'how to solve'. It explains some basic techniques, which should enable you to solve this puzzle.

Last edited by TKiel on Thu Mar 02, 2006 12:16 am, edited 1 time in total.
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Postby Hud » Thu Mar 02, 2006 4:14 am

I'll get you started with a couple basic ones:
In box 5 (the middle one) 4 can only go at r5c6
In box 9 (lower right one) 4 can only go at r9c7
When you finish all the obvious ones, you should use pencilmarks to show candidates.
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Postby MCC » Thu Mar 02, 2006 1:23 pm

Looking at the symmetry it looks like nothing has been added to the original puzzle at all.

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Sudoku help, please

Postby Cec » Thu Mar 02, 2006 2:10 pm

MCC wrote:Looking at the symmetry it looks like nothing has been added to the original puzzle at all.

MCC, unless I'm missing something has this post gone to the right thread?
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Postby MCC » Thu Mar 02, 2006 4:12 pm

Yes Cec

It looks like the original grid was posted by sudoku_n00b and sudoku_n00b has not even attempted to place any numbers at all.

I may be judging sudoku_n00b too harshly here and if I am I apologise.

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Postby QBasicMac » Thu Mar 02, 2006 8:34 pm


Here rows are number 1-9 starting at the top and going down.
Columns are numbered 1-9 starting at the left and going right.
Boxes are numbered 1-3 at the top 4-6 in the middle and 7-9 at the bottom.

OK, look at Box 7, see row 7, column 3. (r7c3)? It is a 4.

It is a 4, thus there can be no more 4's on row 7 or in Box 7, right?

Now r8c4=4 also. So no more 4's on row 8 or in box 8.

Well, Box 9 needs a 4 somewhere. Where can it go?

Right: Either r9c7 or r9c8.

But look up. Above r9c8 is already a 4! So it can't go here.

That leaves only one place: r9c8. You can write a 4 there now.

Keep looking for patterns like that. When there are no more, try this:

Take a row that has som numbers already placed. The more, the better. Then figure out what digits are missing. These have to go into the remaining cells. So one-at-a-time, look at the cells and see if you can eliminate all but one candidate.

For example if you had a row like this:
425 8-1 --3
Then you see that 679 are missing.

Look at the - in 8-1 and see if 6, 7, or 9 are impossible. IF TWO OF THEM are impossible, then it HAS to be the other one. Stick it there.

Well, give it a try and work hard. If you get stuck, post where you got to so we can help.

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