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George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
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 Posted: Thu May 29, 2008 10:37 pm Post subject: May 30 VH |
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Did anyone else solve this by 2 W wings in direct sequence?
I recognize that my solution may well be a transposition of some other technique such as colouring 7s. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri May 30, 2008 4:55 am Post subject: |
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| I did it with multi-coloring on 7 followed by a W-Wing, which is not to say that there wasn't a W-Wing available at first that I missed. |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Fri May 30, 2008 5:37 am Post subject: |
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Here's what I did:
After basics...
| Code: |
+--------------------------+--------------------------+--------------------------+
| 49 2 3 | 8 49 57 | 57 1 6 |
| 47 6 5 | 1 3 2 | 8 9 47 |
| 1 789 48 | 457 4569 567 | 2 457 3 |
+--------------------------+--------------------------+--------------------------+
| 259 589 6 | 359 1 4 | 39 578 257 |
| 3 589 7 | 59 2 58 | 4 6 1 |
| 2459 1 48 | 6 7 358 | 39 58 25 |
+--------------------------+--------------------------+--------------------------+
| 8 57 2 | 3457 456 3567 | 1 457 9 |
| 57 4 9 | 2 58 1 | 6 3 578 |
| 6 3 1 | 457 458 9 | 57 2 4578 |
+--------------------------+--------------------------+--------------------------+
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play online
X-wing on 7 (rows 2 and 8, removes 7 from r49c9). This solves many cells.
Then here:
| Code: |
+--------------------------+--------------------------+--------------------------+
| 49 2 3 | 8 49 57 | 57 1 6 |
| 47 6 5 | 1 3 2 | 8 9 47 |
| 1 79 8 | 457 4569 567 | 2 45 3 |
+--------------------------+--------------------------+--------------------------+
| 259 8 6 | 359 1 4 | 39 7 25 |
| 3 59 7 | 59 2 8 | 4 6 1 |
| 259 1 4 | 6 7 35 | 39 8 25 |
+--------------------------+--------------------------+--------------------------+
| 8 57 2 | 3457 456 3567 | 1 45 9 |
| 57 4 9 | 2 58 1 | 6 3 78 |
| 6 3 1 | 457 458 9 | 57 2 48 |
+--------------------------+--------------------------+--------------------------+
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play online
...UR 25 r46c19 (in order to avoid the deadly pattern, r46c1 must contain 9) solves r1c1=4 and r5c2=9. |
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George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
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| Posted: Fri May 30, 2008 6:26 am Post subject: The Double w wing solution |
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Taking the first grid provided by Nataraj :-
57s in boxes 7,9 operating on row 8 deny a 5 to r7c8 which becomes 47
47s in boxes 3,9 operating on col 7 deny 4 to r3c8 so r2c9 is 4 ..... and
it falls out thereafter!
Last edited by George Woods on Fri May 30, 2008 4:46 pm; edited 1 time in total |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Fri May 30, 2008 7:30 am Post subject: |
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The 25 UR* in R46C19 pins <7> in R2C1, all three solutions for avoiding the possible 25 DP ends up with <7> in R2C1, which succumbs the puzzle.
#1 R46C1=9 => R1C1=4 => R2C1=7
#2 R6C1=4 => R2C1=7
#3 R4C9=7 => R2C9=4 => R2C1=7
| Code: | +-------------------------+-------------------------+-------------------------+
| 49 2 3 | 8 49 57 | 57 1 6 |
| 4=7 6 5 | 1 3 2 | 8 9 47 |
| 1 789 48 | 457 4569 567 | 2 457 3 |
+-------------------------+-------------------------+-------------------------+
|*25+9 589 6 | 359 1 4 | 39 578 *25+7 |
| 3 589 7 | 59 2 58 | 4 6 1 |
|*25+49 1 48 | 6 7 358 | 39 58 *25 |
+-------------------------+-------------------------+-------------------------+
| 8 57 2 | 3457 456 3567 | 1 457 9 |
| 57 4 9 | 2 58 1 | 6 3 578 |
| 6 3 1 | 457 458 9 | 57 2 4578 |
+-------------------------+-------------------------+-------------------------+ |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri May 30, 2008 12:44 pm Post subject: |
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My route was a little longer, and more basic but interesting. After the initial x-wing on <7> to eliminate r49c9, I noticed two finned x-wings on <7> in r37c24 and r37c26. Then I realized that these two "interlocked" finned x-wings were part of a "jellyfish" in r1379c2467 that deleted r9c9 (as did the initial x-wing). The two finned x-wings destroyed each other but I removed the <7> for both: r7c6 and r3c4.
After significant clean-up, I still had to remove the <4> at r7c5 based on coloring to complete the puzzle.
This was the first "jellyfish" that I have actually found!
Ted |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Fri May 30, 2008 1:16 pm Post subject: |
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That UR Johan mentioned is a TYPE 4. Since there are only two 2's in C1 we can remove the 5's from C1 Box4. I know this because I am an expert in Type 4 URs (since last Tuesday).
Though it seems I still had to use an x-wing in R28 to remove a <7> and set up the UR. |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Fri May 30, 2008 2:17 pm Post subject: May 30 VH |
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After the x-wing of 7's, there is an xy-wing (578) in boxes 8&9 which solves the puzzle. There is also an xyz-wing (457) in boxes 2&3, but it does not finish the puzzle.
Earl |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri May 30, 2008 3:08 pm Post subject: |
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| cgordon wrote: | That UR Johan mentioned is a TYPE 4. Since there are only two 2's in C1 we can remove the 5's from C1 Box4. I know this because I am an expert in Type 4 URs (since last Tuesday).
Though it seems I still had to use an x-wing in R28 to remove a <7> and set up the UR. |
In this case, the <5>s inr46c1 are removed by the <7> in r2c1 which makes r8c1=5.
However I understood that a Type 4 UR required the other two cells to be bivalues. In this case, cell r4c9 contains a extra digit so that in fact the solution could have a <5> in either r46c1.
Did I overlook something? 
Ted
Edit: Yes, I did overlook something! The comment by Craig was obviously appropriate after the x-wing removed the <7> inr4c9. (I don't like Friday either.)
Last edited by tlanglet on Fri May 30, 2008 8:12 pm; edited 1 time in total |
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stevieboy
Joined: 25 Jan 2008
Posts: 31
Location: Michigan
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| Posted: Fri May 30, 2008 4:00 pm Post subject: |
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| nataraj wrote: |
...UR 25 r46c19 (in order to avoid the deadly pattern, r46c1 must contain 9) solves r1c1=4 and r5c2=9. |
That's what did it for me, too! |
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Florida Bob
Joined: 25 Jul 2007
Posts: 12
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| Posted: Fri May 30, 2008 4:01 pm Post subject: First x- wing |
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| It must be Friday however, I can't see the x-wing that eliminates the 7's in rows 4 & 9 col. 9. Could someone be more specific. |
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stevieboy
Joined: 25 Jan 2008
Posts: 31
Location: Michigan
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| Posted: Fri May 30, 2008 4:34 pm Post subject: |
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No problem, Florida Bob,
The '7's in Rows 2 and 8, as well as along Column 1 are strong pairs (one or the other cell along those paths HAS to be a '7').
Therefore, in Column 9, the 7 HAS to be in either, in Row 2 or Row 8 - ONE OR THE OTHER.
So, any '7' along the rectangular path mentioned above, CAN NOT contain a '7'.
Take it easy! |
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andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
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| Posted: Fri May 30, 2008 5:58 pm Post subject: |
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It certainly took a little time, but was fun in the end.
Perhaps we need a new category beyone 'VH' for these puzzzles that need multiple advanced techniques. Can I suggest Death By Sudoku? 
John |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri May 30, 2008 7:39 pm Post subject: Re: First x- wing |
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| Florida Bob wrote: | | It must be Friday however, I can't see the x-wing that eliminates the 7's in rows 4 & 9 col. 9. Could someone be more specific. |
the above image shows the 7's in rows 2 and 8. sudoku tells us that a 7 must occupy one of those rows. so regardless which column we put a 7 in, a 7 must go in the other one, ( either col 1 or 9 ) therefore any other 7's in col 1 or 9 can be eliminated.
george woods,
I like the double w-wing approach... I find these easier to find than xy-wings. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri May 30, 2008 7:48 pm Post subject: |
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| andras wrote: | It certainly took a little time, but was fun in the end.
Perhaps we need a new category beyone 'VH' for these puzzzles that need multiple advanced techniques. Can I suggest Death By Sudoku?
John |
do you venture into the "other puzzles" category? |
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andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
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| Posted: Fri May 30, 2008 8:41 pm Post subject: |
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| storm_norm wrote: | | andras wrote: | It certainly took a little time, but was fun in the end.
Perhaps we need a new category beyone 'VH' for these puzzzles that need multiple advanced techniques. Can I suggest Death By Sudoku?
John |
do you venture into the "other puzzles" category? |
I don't dare - I have a life to lead as well as doing Sudoku and crosswords! 
John |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Fri May 30, 2008 10:03 pm Post subject: |
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| andras wrote: |
I don't dare - I have a life to lead as well as doing Sudoku and crosswords!
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But that is only the OTHER life !
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