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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Tue Aug 28, 2007 2:08 pm Post subject: Aug 28 VH |
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Two back-door compact xy-wings, eliminating 3 from R4C4 and 5 from R8C5, leaves only singles.
Earl |
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jLo
Joined: 30 Apr 2007
Posts: 55
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| Posted: Tue Aug 28, 2007 2:34 pm Post subject: |
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The easiest VH in recent memory, I think.
There are a couple of different XY-wings and a couple of
W-Wings after the first XY-wing that Earl noted, any one of
which breaks the whole thing open. |
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George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
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| Posted: Tue Aug 28, 2007 4:14 pm Post subject: completely different solution |
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| Code: |
+---------+--------------+----------+
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
+---------+--------------+----------+
| 8 9 24 | 346 34 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 59 569 | 26 4 8 |
+---------+--------------+----------+
| 45 6 1 | 8 3459 359 | 35 7 2 |
| 7 2 9 | 1 345 356 | 356 8 46 |
| 45 8 3 | 456 7 2 | 1 9 46 |
+---------+--------------+----------+
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Play this puzzle online at the Daily Sudoku site
For me I noticed that r4c4 acts as a hinge to a type of wing:- If 6 then the 45s in col4 deny a 5 in r1c4 and if not a 6 then the 34s make r5c4 5 again denying a 5 to r1c4 which must be 3, two moves further on a BUG+1 arises and from there it is plain sailing.
Many ways to skin a cat! |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Aug 28, 2007 7:06 pm Post subject: |
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| I just couldn't find any wings, not X, XY, XYZ or W. The grid above should not have a 6 in r8c7. I solved a cell based on the implications of that 35 UR in boxes 8 and 9. After the eliminations therefrom, that 35 rectangle became a Type 1 which solved the puzzle. |
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sdq_pete
Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL
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| Posted: Tue Aug 28, 2007 7:55 pm Post subject: |
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Well, I know that the XY wing with pivot 45 at R5C4 and pincers 35 and 34 at R1C4 and R4C5, eliminating the 3 at R4C4, opened the "end phase" for me.
Peter |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Aug 28, 2007 9:55 pm Post subject: |
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| Quote: | | Well, I know that the XY wing with pivot 45 at R5C4 and pincers 35 and 34 at R1C4 and R4C5, eliminating the 3 at R4C4, opened the "end phase" for me. |
I never cease to be amazed at how much I can miss that's right out there in plain view.  |
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TKiel
Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI
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| Posted: Wed Aug 29, 2007 8:53 pm Post subject: |
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| Quote: | | I never cease to be amazed at how much I can miss that's right out there in plain view. |
Wouldn't we all be better solvers (and people, too) if this never happened?
And, not that it's only applicable to this puzzle, I can't recall a prior run of 5 VH's in 9 days. Three cheers for Sam! |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Thu Aug 30, 2007 6:43 pm Post subject: |
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| Quote: | | The easiest VH in recent memory, I think. |
Not sure about that !
I had to use two xy wings and one x wing (which seems typical from posts). Many of recent VHs required only one xy - or even one x wing. |
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Myth Jellies
Joined: 27 Jun 2006
Posts: 64
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| Posted: Thu Aug 30, 2007 8:16 pm Post subject: Re: completely different solution |
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| George Woods wrote: | | Code: |
+---------+--------------+----------+
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
+---------+--------------+----------+
| 8 9 24 | 346 34 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 *59 *569 | 26 4 8 |
+---------+--------------+----------+
| 45 6 1 | 8 *3459*359 |*35 7 2 |
| 7 2 9 | 1 *345 *356 |*35 8 46 |
| 45 8 3 | 456 7 2 | 1 9 46 |
+---------+--------------+----------+
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...Many ways to skin a cat! |
Here is another that isn't too hard to see, but you don't find it too often. The starred cells (r6c56, r7c567, r8c567) are in danger of forming a MUG using the digits 3569. The only way to avoid the MUG is to have r78c5 = 4 which eliminates the 4's in r4c5 and r9c4. After solving a few cells, you are left with a simple BUG+1 grid to finish. |
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KSipher
Joined: 24 Sep 2006
Posts: 38
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| Posted: Sat Sep 01, 2007 1:42 am Post subject: 8/28 Still stuck |
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Hi
I am stuck at this point. Can someone suggest what to look for?
Thanks
Kathy
| Code: |
+---------+-----------+---------+
| 1 4 7 | 3 6 5 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
+---------+-----------+---------+
| 8 9 24 | 46 3 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 59 69 | 26 4 8 |
+---------+-----------+---------+
| 45 6 1 | 8 459 39 | 35 7 2 |
| 7 2 9 | 1 45 36 | 35 8 46 |
| 45 8 3 | 56 7 2 | 1 9 46 |
+---------+-----------+---------+
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Play this puzzle online at the Daily Sudoku site |
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KSipher
Joined: 24 Sep 2006
Posts: 38
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| Posted: Sat Sep 01, 2007 1:50 am Post subject: BUG?? |
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Hi,
I just posted a question and now I am wondering if this is a sample of a BUG removal? If I remove the 5 from row 7 column 5, then is this a sample of a BUG? So does that mean that row 7 column 5 must be a 5??
| Code: |
+---------+-----------+---------+
| 1 4 7 | 3 6 5 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
+---------+-----------+---------+
| 8 9 24 | 46 3 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 59 69 | 26 4 8 |
+---------+-----------+---------+
| 45 6 1 | 8 459 39 | 35 7 2 |
| 7 2 9 | 1 45 36 | 35 8 46 |
| 45 8 3 | 56 7 2 | 1 9 46 |
+---------+-----------+---------+
|
Play this puzzle online at the Daily Sudoku site
Thanks for your help
Kathy |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Sep 01, 2007 3:48 am Post subject: |
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| Kathy, yes to all your questions. The pattern in your grid is usually referred to as a BUG+1. |
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KSipher
Joined: 24 Sep 2006
Posts: 38
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| Posted: Sat Sep 01, 2007 5:41 pm Post subject: BUG!! |
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Awesome, I found my first BUG and I even understand it!!
Thanks,
Kathy |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Thu Mar 04, 2010 8:01 am Post subject: Re: completely different solution |
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| Myth Jellies wrote: | | George Woods wrote: | | Code: |
+---------+--------------+----------+
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
+---------+--------------+----------+
| 8 9 24 | 346 34 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 *59 *569 | 26 4 8 |
+---------+--------------+----------+
| 45 6 1 | 8 *3459*359 |*35 7 2 |
| 7 2 9 | 1 *345 *356 |*35 8 46 |
| 45 8 3 | 456 7 2 | 1 9 46 |
+---------+--------------+----------+
|
...Many ways to skin a cat! |
Here is another that isn't too hard to see, but you don't find it too often. The starred cells (r6c56, r7c567, r8c567) are in danger of forming a MUG using the digits 3569. The only way to avoid the MUG is to have r78c5 = 4 which eliminates the 4's in r4c5 and r9c4. After solving a few cells, you are left with a simple BUG+1 grid to finish. |
I'm wondering if any of you mugs could help me out with this one. I know this is ancient history, but I found it while doing a little research.
I cannot see the MUG on (3569). The (6)s don't seem right in there. I guess the L-shape might be throwing me off.
What am I missing? |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Thu Mar 04, 2010 6:20 pm Post subject: |
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here is a link to the pattern.
http://www.sudoku.com/boards/viewtopic.php?t=3210&start=0
but I agree with you Luke, I am scratching my head over this one.
if we apply what the pattern is we get this
| Code: | +-------+------------+--------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+------------+--------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . 59 569 | . . . |
+-------+------------+--------+
| . . . | . 3459 359 | 35 . . |
| . . . | . 345 . | 35 . . |
| . . . | . . . | . . . |
+-------+------------+--------+ |
according to Myth Jellies,
the deadly pattern is
| Code: |
+-------+----------+--------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+----------+--------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . 59 59 | . . . |
+-------+----------+--------+
| . . . | . 359 59 | 35 . . |
| . . . | . 35 . | 35 . . |
| . . . | . . . | . . . |
+-------+----------+--------+
|
the extra candidates in the grid are
6 in r6c6
3 in r7c6
4's in r78c5
so the question is how are the 4's solely responsible for the destruction of the deadly pattern? |
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strmckr
Joined: 18 Aug 2009
Posts: 66
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| Posted: Fri Mar 05, 2010 5:57 am Post subject: |
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| Code: | +-------+----------+--------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+----------+--------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . 59 59 | . . . |
+-------+----------+--------+
| . . . | . 359 59 | 35 . . |
| . . . | . 35 . | 35 . . |
| . . . | . . . | . . . |
+-------+----------+--------+
|
with in the pattern displayed above there is both a
35-35
35-35
unique rectangle & a
59 - 59
59 - 59
unique rectangle
rectangle linked as 1 unit where by any combination of 3/5/9 yields 2 solution outcomes.
the only way to prevent the pattern from completing either or is to have one of the two cells in question = 4.
R8C5 or R7C5
so yes the 4 is responsible for preventing that pattern from completing.
so any 4 out side the pattern that sees these two cells must be false
ie R4C5 <> 4
in regards to the mug
| Code: | +---------+--------------+----------+
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
+---------+--------------+----------+
| 8 9 24 | 346 34 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 *59 *569 | 26 4 8 |
+---------+--------------+----------+
| 45 6 1 | 8 *3459*359 |*35 7 2 |
| 7 2 9 | 1 *345 *356 |*35 8 46 | notice the bi location of 4 & 6
| 45 8 3 | 456 7 2 | 1 9 46 |
+---------+--------------+----------+
|
---------------------(notice the bi location of 6 on the column |
if R8C9 = 6 then R8C5 =4 (bug is avoided)
if R8C9 = 4 then R7C5 =4 (bug is avoided)
if R7C6 = 6 => R8C9 = 4 => R7C5=4 (bug is avoided)
(the bug being displayed above)
this is why it is called multivalued.
no matter how specific digits are arranged the bug still is present or avoided. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri Mar 05, 2010 2:59 pm Post subject: |
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| Quote: | if R8C9 = 6 then R8C5 =4 (bug is avoided)
if R8C9 = 4 then R7C5 =4 (bug is avoided)
if R7C6 = 6 => R8C9 = 4 => R7C5=4 (bug is avoided)
(the bug being displayed above)
this is why it is called multivalued.
no matter how specific digits are arranged the bug still is present or avoided |
why didn't Myth Jellies explain it this way? |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Fri Mar 05, 2010 3:15 pm Post subject: |
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Gents, first off, thanks for looking at that for me. I'm still not outta the woods, tho.
No biggie, but it has to be misleading to say this is a (3569) MUG.
| storm_norm wrote: | the extra candidates in the grid are
6 in r6c6
3 in r7c6
4's in r78c5 |
StrmCkr, do you agree that these are the "internal outs?"
| Code: | *-----------------------------------------------------------*
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
|-------------------+-------------------+-------------------|
| 8 9 24 | 346 -43 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 *59 *59+6 | 26 4 8 |
|-------------------+-------------------+-------------------|
| 45 6 1 | 8 *359+4 *59+3 |*35 7 2 |
| 7 2 9 | 1 *35+4 356 |*35 8 46 |
| 45 8 3 |-456 7 2 | 1 9 46 |
*-----------------------------------------------------------* |
How do you account for (3)r7c6 leading to the two -(4)s?
| StrmCkr wrote: | | if R8C9 = 4 then R7C5 =4 (bug is avoided) |
Sorry, Seeker, I must have blinders on. I don't see that either  .
Below is another (359) MUG, with no L-shape into box 9. I can’t get the elims from this one either, though!
| Code: | *-----------------------------------------------------------*
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
|-------------------+-------------------+-------------------|
| 8 9 24 | 346 43 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 *59 *59+6 | 26 4 8 |
|-------------------+-------------------+-------------------|
| 45 6 1 | 8 *359+4 *359 | 35 7 2 |
| 7 2 9 | 1 *35+4 *35+6 | 35 8 46 |
| 45 8 3 | 456 7 2 | 1 9 46 |
*-----------------------------------------------------------* |
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strmckr
Joined: 18 Aug 2009
Posts: 66
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| Posted: Sat Mar 06, 2010 12:37 am Post subject: |
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| Code: | *-----------------------------------------------------------*
| 1 4 7 | 35 6 35 | 8 2 9 |
| 2 3 6 | 9 8 4 | 7 1 5 |
| 9 5 8 | 2 1 7 | 4 6 3 |
|-------------------+-------------------+-------------------|
| 8 9 24 | 346 3-4 1 | 26 5 7 |
| 6 7 45 | 45 2 8 | 9 3 1 |
| 3 1 25 | 7 *59 *59+6 | 26 4 8 |
|-------------------+-------------------+-------------------|
| 45 6 1 | 8 *359+4 *359 | *35 7 2 |
| 7 2 9 | 1 *35+4 *35+6 | *35 8 46 |
| 45 8 3 | 56-4 7 2 | 1 9 46 |
*-----------------------------------------------------------* |
u posted the same grid twice?
there is a Hidden Rectangle: 5/9 in r6c56,r7c56 => r7c6<>5
& the mug as well.. |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Sat Mar 06, 2010 2:27 am Post subject: |
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| strmckr wrote: |
u posted the same grid twice?
there is a Hidden Rectangle: 5/9 in r6c56,r7c56 => r7c6<>5
& the mug as well.. |
Same grid, yes, but if you look closely, the second MUG is not the same as the first. My point is, I can't see how either takes out the (4)s in the original post.
I see the hidden UR elim, but my bete noire is the MUG, not URs.
I'll put it aside for a few days. When I look again, I'm sure the clouds will part. |
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