Author |
Message |
Topic: "Coloring" |
David Bryant
Replies: 5
Views: 39649
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Forum: Other puzzles Posted: Tue Oct 17, 2006 12:56 am Subject: Well, ... |
Hi, Paladin! Haven't heard from you in quite a while.
You've reached a valid conclusion, but I can't quite follow your logic. Here's the problem.
r1c4 (+) --> r1c5 --> r7c5 --> r9c6 --> ... |
Topic: Another "technique" added to V Hard? |
David Bryant
Replies: 1
Views: 30935
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Forum: General discussion Posted: Fri Oct 13, 2006 11:04 am Subject: I found an X-Wing |
Hi, George!
We'll have to ask SamGJ to weigh in here about adding new techniques. I don't think you need to use anything beyond X-Wings to solve his puzzles, yet, but I'm not certain.
On the puzzle ... |
Topic: What's the logic behind remote naked pairs |
David Bryant
Replies: 2
Views: 40035
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Forum: General discussion Posted: Thu Oct 05, 2006 3:02 pm Subject: It depends ... |
Hi, Kowloon!
I'm not certain I understand your question, but maybe this is what you're asking about. 46+ . . . . . * . . . . . . . . . . ... |
Topic: Aug 26 help please |
David Bryant
Replies: 4
Views: 32006
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Forum: Daily Sudoku puzzles Posted: Tue Oct 03, 2006 11:55 pm Subject: Hidden pair in column 3 |
Hi, Kathy!
If you look closely you'll find a "hidden pair" {4, 5} in column 3 -- specifically, in r2c3 and r8c3. So the only spot in row 2 where the "9" can possibly fit is at r2c4.
Oh -- I often fi ... |
Topic: Sept. 28th Nightmare |
David Bryant
Replies: 7
Views: 48295
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Forum: Other puzzles Posted: Sat Sep 30, 2006 7:49 pm Subject: Terminology |
I've always thought of a constellation as an XY-chain (bivalue cells only) but this one passes through a cell that is solved (r7c6) and one that has 3 candidates (r5c8). Am also wondering if the 'alph ... |
Topic: Sept. 28th Nightmare |
David Bryant
Replies: 7
Views: 48295
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Forum: Other puzzles Posted: Sat Sep 30, 2006 1:46 pm Subject: 5-star constellation |
That's a very nice analysis, Matt. I particularly like the way you noticed how the two "X-Wings" intersect each other ... I missed that entirely, although I did find the same "anomaly" when I worked t ... |
Topic: Sep 29 - Logic behind an elimination? |
David Bryant
Replies: 5
Views: 43288
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Forum: Daily Sudoku puzzles Posted: Fri Sep 29, 2006 5:52 pm Subject: Have you learned the "X-Wing"? |
Hello, Blackwood!
The short answer is that you have an "X-Wing" formation in columns 1 and 6, on digit 7. In other words, since there are only two places to fit a "7" in column 1 (at r6c1 or r9c1) an ... |
Topic: Squiggly Sun Sep 24 2006 |
David Bryant
Replies: 3
Views: 160379
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Forum: Daily Sudoku Squiggly puzzles Posted: Thu Sep 28, 2006 4:12 pm Subject: Check this explanation |
Hi, wfbeach!
I don't think there are two solutions. Maybe you noticed the same thing Louise56 was worried about ... check out [url=http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=1541]this p ... |
Topic: DB Saturday Puzzle - September 23, 2006 |
David Bryant
Replies: 34
Views: 148949
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Forum: Other puzzles Posted: Sun Sep 24, 2006 6:53 pm Subject: In defense of "nishio" |
"A rose by any other name would smell as sweet." The original description/method of nishio is the following: For a grid focused on a single digit. Assume that digit occupies a certain start cell. If, ... |
Topic: X-Wing & XY -Wing |
David Bryant
Replies: 12
Views: 95941
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Forum: General discussion Posted: Sun Sep 24, 2006 3:19 am Subject: Play it again, Sam ... |
Hi, Jake! Thanks for writing back. And thanks for the diagram. Specific examples are easier to follow than abstract explanations. 1xx|x1x|xx1 xxx|x1x|xx1 1xx|x11|1xx ----------- xxx|xxx|xxx xxx|x11|1x ... |
Topic: DB Saturday Puzzle - September 23, 2006 |
David Bryant
Replies: 34
Views: 148949
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Forum: Other puzzles Posted: Sun Sep 24, 2006 12:00 am Subject: What an interesting thread! |
Wow! We have a very good discussion going this time. Thanks for posting this puzzle, Keith. The original name for the "empty rectangle" was "hinge", which I think is more descriptive. You will find mo ... |
Topic: DB Saturday Puzzle - September 23, 2006 |
David Bryant
Replies: 34
Views: 148949
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Forum: Other puzzles Posted: Sat Sep 23, 2006 8:00 pm Subject: Look at "Nishio" / "Empty Rectangle" |
... but there might be a more sophisticated solution which eludes me. At this point in the puzzle there are a couple of "Nishio" moves that will solve it. *------------------------------------------- ... |
Topic: X-Wing & XY -Wing |
David Bryant
Replies: 12
Views: 95941
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Forum: General discussion Posted: Fri Sep 22, 2006 10:32 pm Subject: Which are you asking about? |
Hi, Jake!
I'm a little confused by your post. Are you asking abou the "X-Wing" pattern? Or about the "XY-Wing"? Since you mentioned a rectangle, I suppose you're asking about the "X-Wing".
The first ... |
Topic: If you want to learn about fishing... |
David Bryant
Replies: 16
Views: 99753
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Forum: Other puzzles Posted: Thu Sep 21, 2006 6:52 pm Subject: It's a finned X-Wing |
Did you note the squirmbag (so called per Marty above -- a five-level x-wing I think) on the 2s removing the 2 from the {127} in r9c2 and leaving a bivalue cell. I am trying like heck to make that cri ... |
Topic: If you want to learn about fishing... |
David Bryant
Replies: 16
Views: 99753
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Forum: Other puzzles Posted: Thu Sep 21, 2006 12:01 am Subject: Well, maybe it wasn't so basic ... |
Hi, Matt!
You're right -- I did have to depend on a "finned swordfish" to eliminate the "5" at r2c5. And having a pair in that cell is essential to the forcing chains I found. I guess the "finned swo ... |
Topic: If you want to learn about fishing... |
David Bryant
Replies: 16
Views: 99753
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Forum: Other puzzles Posted: Wed Sep 20, 2006 10:12 pm Subject: Using chains to solve this one |
Here's how I solved this puzzle. The first time through I concentrated on r4c5; going over it again, I noticed that it's easier to work from r5c2. Basic stuff got me here. *--------------------------- ... |
Topic: If you want to learn about fishing... |
David Bryant
Replies: 16
Views: 99753
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Forum: Other puzzles Posted: Wed Sep 20, 2006 6:01 pm Subject: This is a hard one |
Hi, Matt!
I did solve this puzzle by concentrating on two "double-implication chains". The first one started from r4c5, and the second one (later) started from r6c5. I'll have to reconstruct it befor ... |
Topic: challenging puzzle looking for help 1 through 9 |
David Bryant
Replies: 1
Views: 31085
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Forum: General discussion Posted: Wed Sep 20, 2006 1:38 pm Subject: It can't be done |
Hi, Dan!
That's not a sudoku puzzle. It sounds like a magic square.
Clearly if it's a 3x3 square it's impossible. Since the sum of the digits 1 - 9 is 45, and every digit would be included in two su ... |
Topic: Naked singles on Sudoku |
David Bryant
Replies: 2
Views: 27311
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Forum: Daily Sudoku puzzles Posted: Tue Sep 19, 2006 1:30 pm Subject: Poorly phrased question |
Hi, Jeff!
I'm not sure I understand your question, but I'll give the best answer I can.
The only way to "solve" a cell in a sudoku puzzle is to reduce it to the status of either a hidden single or a ... |
Topic: Brown Belt 9 |
David Bryant
Replies: 2
Views: 32034
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Forum: Other puzzles Posted: Sun Sep 17, 2006 1:48 pm Subject: Line/Box interaction |
Hi, Pete!
The hint relies on "line/box interaction".
The "3" in the lower right 3x3 box must lie in column 7. Therefore there cannot be a "3" at r1c7, leaving "2" as the sole candidate. dcb |
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