### Help - Please

I've already done this successfully once, but I was trying to show off to my husband... Serves me right, doesn't it? Could someone please tell me the next step? I have no idea how I got it before - I didn't guess on any of the numbers, so what am I missing this time?

## 9 Comments:

Is it hopscotch............?

It is very hard, and also I find it hard to do a puzzle that has been half completed. But I think this might be it:

Call the vertical lines columns and the horzontal lines rows. I think the fourth hole in row 1 has to be an 8.

Why? Look at the top right-hand "square of 9", and those 4 empty holes. They have to be 28 48 (row 2) and 23 43 (row 3), as there are only 4 numbers in total.

If I'm right (not 100 per cent convinced I am), there is only one place in the middle top "matrix of 9" that can be an 8.

So it is being stumped by a sudoku that finally gets you to blog, huh? ;-)

By the way, Susan, sorry, I forgot to mention this to you -- I think you are the only person in the world apart from me who has "petrona pieces" in her blogroll! This blog is now defunct, or at least, an archive, as I no longer use Bloglines.

The equivalent is my "shared Google Reader items" -- if you want to link to that, you can see it under "my links" or at: http://www.google.com/reader/shared/17539876627300326705

but please, please, please, don't bother linking to it unless you have the least interest in it. I shan't be at all offended if you don't, it isn#t a proper blog, just a set of clippings.

It makes a pretty satisfying pattern but THAT'S all I can say. Sorry. My mathematical leanings All fell out out of the window when I was 14.

I think I must have lost a mass of grey matter in the space of a few days, because I just can't see it even when you explain it to me, Maxine. Thank you for trying... I feel like such a clod, because honestly I did figure it out once!

Jan, you're probably much more capable than I am at these things. I only started them recently...actually, I learned when Debra Hamel had a Sudoku component in a contest she ran within the last six months. I've been *working* at it and I can often do the difficult ones (I originally did this one in the space of about half an hour!) I copied it for my husband, convinced that his lack of interest would make it impossible for him. I hoped to dazzle him with my own brilliance. I'm dazzling alright. About as dazzling as a mud puddle.

Across the top line, where it goes 1, 5, 7, try an 8 as the next number along. Then it goes 4. 3. 6, blank (which will be a 2), finally the 9.

I could be wrong, Susan, forgive me if so.

Less of this mud puddle, please! I spent an hour on one this morning and was infuriated when the last few squares showed me I had got something wrong, somewhere. Hubris (as I had previously been saying something along the lines that I'd got killer sudokus taped).

Some of them are just b****** difficult, don't be so hard on yourself. Remember it is probably a computer program that made the darn thing, which is what I'd call an "unfair advantage" over us mere humans!!!

I think you are a clever woman, cleverer than you admit.

My general strategy is to scan boxes, rows and columns for things that are determined. If nothing comes of that, I look at pairs of squares in a box, row or column that can only have the same two numbers, and use them to try and find a contradiction or tautology.

F'rinstance, in row 1, square 4 and square 8 can only have either a 2 or an 8. Suppose that row 1, column 4 was a 2. That would mean row 6, column 5 was a 2. That would mean row 5, column 7 was a 2. That would mean row 6, column 6 would be a 1. That would mean row 2, column 6 would be a 1. That would also mean row 6, column 3. That would mean row 4, column 3 would be a 1. That would mean row 4, column 5 would be a 9. That would mean row 4, column 4 would be an 8. That would mean that row 5, column 1 would be an 8. That would mean row 5, column 3 would be a 5. That would mean row 5, column 4 would be a 3. That would mean row 8, column 4 would be a 5. That would mean row 8, column 5 would be a 3. That would mean row 7, column 3 would be an 8. That would mean row 7, column 2 would be a 3. That would mean row 8, column 2 would have to be a 7. That would mean row 7, column 8 would have to be a 7. That would mean row 7, column 9 would have to be a 5. That would mean row 6, column 9 would have to be an 8. That would mean row 6, column 7 would have to be a 5. That would mean row 3, column 7 would have to be an 8. But row 3, column 7 can't be an 8, because row 1, column 8 has to be an 8, because of our original assumption that row 1, column 4 is a two. The point of all this is that putting a 2 in row 1, column 4 leads to a contradiction, therefore, 8 has to go in row 1, column 4, which leads to another series of consequences.

So, based on the previous comment, row 1, column 4 is an 8, which means row 1, column 8 is a 2, which means row 8, column 9 is a 2.

row 1, column 4 being an 8 also means row 2, column 6 is a 1, which means row 6, column 6 is an 8, which means row 5, column 7 is an 8, which means row 4, column 3 is an 8, which means row 5, column 1 is a 3, which means row 5, column 3 is a 5, which means row 6, column 3 is a 1, which means row 7, column 3 is a 3, and row 4, column 5 is a 1, which means row 4, column 4 is a 9, which means row 2, column 5 is a 9...well, at any rate, you're unstuck...

Thank you, Douglas! I've printed out your comments and I'm going to study them tonight and try to comprehend the sequence of thought... Bless your heart for taking the time to help!

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