Do lock pairs work around corners?

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Do lock pairs work around corners?

Postby RyanStorm » Mon May 05, 2014 11:39 pm

I am doing a super hard Super Sudoku. In the very bottom right cell, r16c16, I got 7, D or E. Above it, in same column I got a D or E, and to the left of the r16c16, I got a 7 or D.

Based on lock pairs, if they were in same row or column, I could erase all 7, D and E's from that row/column.

Question 1:
I am wondering if that same thing works even if all three aren't in same row/column? Where boxes labeled 2 and 3, are connected to box labeled 1.

1= 7DE
2 = 7D
3 = DE

Image

Question 2:
Also, I was wondering if locked pairs work, even if in sets of 3, and odd number? I got 3 boxes with DE's, if you look at the DE labeled 3 on picture, below it I got a box with 1, 3, 7, D or E, to the left of that box is another DE. Based on DE being in same row, and same column, doesn't that mean I can erase the DE from the 137DE box?? I have this exact same thing on the other side of the puzzle, where I got a set of three boxes in same positions as the DE's but they are OA, but where 137DE is, on this other setup, I got a box with OAC.

My problem is, I looked at answer sheet, and I know for a fact that DE is not in the 137DE box, and that OA is not in the OAC box. But I thought it might be coincidence, I just wanted reassurance that it is a real move, and not just coincidence.

Question 3:
In a house not shown, I got 4 boxes left, I got 2 boxes with 37C, I then got a 3rd box with 357C, and a last box with 57C. With the two being 37C, and a 3rd box having those three numbers in it, does that allow me to erase the 7C from the 57C box?
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Re: Do lock pairs work around corners?

Postby RyanStorm » Mon May 05, 2014 11:57 pm

I am really interested in question 3, because I calculated it, and if that is true it opens this puzzle up big time, and original question won't really matter at all.

To reiterate Question #3, in the picture below, I want to remove the 7C, from the 57C box, based on the fact that in same house I got 37C being in two boxes, and a third box with 357C. I was under impression, in this scenario, that I could erase the 5 from 357C. Then those 3 boxes would be a triple set, of those 3 potential answers. Which of course would make 57C, a 5.

Image
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Re: Do lock pairs work around corners?

Postby JasonLion » Tue May 06, 2014 2:59 am

No eliminations are possible in that last photo without information from the rest of the puzzle.

For question 1, the three cells must all share either a row, column, or block.

For question 2, that is a valid elimination and is called a unique rectangle type one.
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Re: Do lock pairs work around corners?

Postby RyanStorm » Tue May 06, 2014 6:47 am

Yeah that technique from question 2, was actually used like 4 times in the Sudoku, and that is my new favorite trick to look for, it always seems to happen, cause many boxes end up with last two potential answers.

I knew the first one was a long shot. I have been waiting to get a sudoku that has that on it so I can use it. I saw it on the brainbashers thing, then noticed what I had, but when I XY'd them, it didn't turn out like I thought, I thought I would get answers no matter which were used.

Super Sudoku isn't actually that fun, it is mostly time consuming of techniques I already know. Personally I like advanced regular sudokus. It is an actual mental challenge where you need to learn new stuff and adapt. I thought more boxes meant harder techniques, but it same stuff.
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Re: Do lock pairs work around corners?

Postby RyanStorm » Tue May 06, 2014 6:54 am

I finished it. It was just a slow process of eliminating everything down. I basically used stuff I learned from other puzzles. I don't think I will do any more of those.
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Re: Do lock pairs work around corners?

Postby m_b_metcalf » Tue May 06, 2014 8:51 am

RyanStorm wrote:I thought more boxes meant harder techniques, but it same stuff.

Quite. The larger puzzles are harder only in the sense that, for any given level of difficulty, there is more work to do and so more room for error. In a similar vein, the French newspaper Le Monde is currently publishing puzzles that it describes as 'extreme' but this is really only because they have just 17 givens. The solutions are relatively eay, it's just a slog.

Regards,

Mike Metcalf
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