SudoCue Users

Ruud,

You say you are looking for examples. If you ignore solving by a UR, this is an example of Medusa multi-coloring:

http://www.dailysudoku.com/sudoku/forum ... php?p=9006

Best wishes,

Keith

The Daily Sudoku "very hard" puzzles require (at most) X-wing, XY-wing or XYZ-wing techniques.

http://www.dailysudoku.com/sudoku/

So, X-wings are fairly common in these puzzles.

Keith

Ruud,

This is a BUG-Lite Clearly, I am about to learn something

Keith

Today's Nightmare is kind of special! 000001607908070010020000000036005000004060900000200460000000050090030108802700000 Applying the usual, plus an XY-wing and a Type 2 UR, you get here: +----------------------+----------------------+----------------------+ | 34 45 35 | 89 289 1 | 6 289 7 | | 9 6 8 ...

Hi, Ruud:

Today's Nightmare (Monday, June 12, 2006) has a full house: Types 1, 2, 3, and 4 Unique Rectangles. And then, one more, which is an untyped variant of a Type 6.

Keith

Today's Nightmare can be solved with basic methods and a single Unique Rectangle.

If you do not use the UR, the solution is much tougher.

David, is there a constellation lurking in this particular UR?

(I came late to solve May 11, and found I was early to May 12!)

Best wishes,

Keith

David said: I think this connection between "non-unique rectangles" and double-implication chains is fascinating ... I'd like to understand what causes it to be so. dcb Doubly so, because the UR's have the extra assumption of uniqueness. Or, is it that the UR pattern is useful even if uniq...

Today's puzzle is interesting. With possibilities, the starting point is: +----------------------+----------------------+----------------------+ | 5 29 289 | 4 6 1789 | 3 12 127 | | 7 4 2369 | 2359 19 159 | 1256 8 12 | | 238 1 2368 | 23578 8 578 | 9 2456 247 | +----------------------+---------------...

David, My message was not really to you: It was to those who rant and rave over other people's solution techniques. I am also a logic person, but I think my logic is pattern recognition. Your logic is (I think) more to do with implications and consequences. Do you do jigsaw puzzles? My style is to s...

David,

My entire message was not intended to be taken too seriously.

Keith

David, So, we recognize a UR (and its result) and then we find another way to reason the same result. This is logically defensible as not using Uniqueness? Actually, it seems to me: Assume the deadly pattern, if it is a unique puzzle, you should pretty soon find a contradiction. (And then we'll have...

According to Sudoku Susser, this is not a valid puzzle (it does not have a unique solution): +----------------------+----------------------+----------------------+ | 2 4789 5 | 348 34 4 | 6 3478 1 | | 3 1468 68 | 1468 7 9 | 248 248 5 | | 14689 146789 6789 | 13468 123456 12456 | 23489 23478 23479 | +...

David, and with apologies to Ruud. (Off topic.) Is Someone_Somewhere still somewhere out there? I am not sure it is one of his Zen Sudoku's, but Emily's puzzle has a community, who have not yet solved it. Keith ...|.79|3.. 1..|.3.|... ..8|.26|..9 ----------- 4.1|...|..6 .59|...|..7 ...|...|15. -----...

I get to a stage where all the possibilities are pairs, except for four squares which each have three possibilities. If I can eliminate <7> from three of these squares, the fourth solves the puzzle with a BUG. Except, I cannot find a reasonable way to resolve the <7>'s. +-------------+-------------+...

MJ, Yes, I noticed that the Type-6 reduction on abcd leads to a Type-1 reduction on defg which means g = <8>. I did not have a name for it, and did not see it as a single pattern. In the situation I posted, I did not see any immediate reductions of defg, if you ignore abcd. It also seems, though I h...