| View previous topic :: View next topic |
| Author |
Message |
George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
|
 Posted: Sat May 31, 2008 2:02 pm Post subject: Do the June 4 Very Hard at the previous weekend! |
 |
|
Some of you will have more time to do the real puzzles i.e. the VH on a Sunday rather than a Wednesday. So here is a cheat.
Set your computer clock to Wednesday the 4th June. Now got to Daily Sudoku, and go to Draw/Play. hIt the "Today" button and up will comes next Wednesday's VH puzzle. Now "Print" will give you a hard copy to enjoy over the weekend!
(Edited by Marty to show the puzzle date in subject line). |
|
| Back to top |
|
 |
crunched
Joined: 05 Feb 2008
Posts: 168
|
| Posted: Tue Jun 03, 2008 11:06 pm Post subject: |
|
|
I an anxious to see how others figure this one out. I am utterly stymied. There are lots of skyscrapers and wing-links here, but I just can't ever seem to solve puzzles with bugs, fish, W, M, skyline or exotic solutions.
Assuming that only x, xy or xyz wings are required to solve these puzzles, I would like to see the solutions that way. But skyline or any other solution would be interesting to see. The puzzle, as far as I got, is as follows:
| Code: |
+------------+---------+------------+
| 39 4 1 | 5 6 8 | 2 39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 69 1 689 |
+------------+---------+------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 29 29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+------------+---------+------------+
| 269 1 4 | 7 58 29 | 69 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269 |
| 7 25 3 | 6 58 29 | 1 4 289 |
+------------+---------+------------+
|
Play this puzzle online at the Daily Sudoku site |
|
| Back to top |
|
|
kragzy
Joined: 01 May 2007
Posts: 112
Location: Australia
|
| Posted: Tue Jun 03, 2008 11:22 pm Post subject: |
|
|
Hi Crunched,
There is an xyz wing in box 9. After that, you need to do a fair bit of cleaning up again. Then finally you will find an xy wing that solves the puzzle. Took me about 40 minutes - a lot of going back over and making sure that I had not missed any easy pickings.
Cheers |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Wed Jun 04, 2008 1:14 am Post subject: |
|
|
| crunched wrote: | I an anxious to see how others figure this one out. I am utterly stymied. There are lots of skyscrapers and wing-links here, but I just can't ever seem to solve puzzles with bugs, fish, W, M, skyline or exotic solutions.
Assuming that only x, xy or xyz wings are required to solve these puzzles, I would like to see the solutions that way. But skyline or any other solution would be interesting to see. The puzzle, as far as I got, is as follows:
| Code: |
+------------+---------+------------+
| 39 4 1 | 5 6 8 | 2 39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 69 1 689 |
+------------+---------+------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 29 29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+------------+---------+------------+
| 269 1 4 | 7 58 29 | 69 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269 |
| 7 25 3 | 6 58 29 | 1 4 289 |
+------------+---------+------------+
|
Play this puzzle online at the Daily Sudoku site |
This is not a solution, but just a little W-Wing exercise. The 29 pairs in r3c1 and r7c6 are connected by the 9s in column 7. The pincers (2) take out the 2 from r7c1. It's well worth the effort to learn W-Wings because they show up often enough to make them a very valuable part of the arsenal.
P.S. Updated a few hours later. I got further along with the basics than the above grid and the W-Wing was all that was needed. I didn't even realize I was doing the same puzzle until that W-Wing looked awfully familiar. |
|
| Back to top |
|
|
andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
|
| Posted: Wed Jun 04, 2008 8:44 am Post subject: |
|
|
| kragzy wrote: | Hi Crunched,
There is an xyz wing in box 9. After that, you need to do a fair bit of cleaning up again. Then finally you will find an xy wing that solves the puzzle. Took me about 40 minutes - a lot of going back over and making sure that I had not missed any easy pickings.
Cheers |
That's what I found - quite a straightforward puzzle, I thought.
John |
|
| Back to top |
|
|
George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
|
| Posted: Wed Jun 04, 2008 12:33 pm Post subject: er (9) in box 7 |
|
|
The 9s in box 7 along with the strong link on 9s in col7 mean that r3c3 cannot be 9
Later either a simple W wing or XY wing or maybe neither is needed to finish it off
Testing this on draw/play the ER still left a puzzle graded as VH, but put in Marty Rs W wing and it is graded as easy!
Last edited by George Woods on Wed Jun 04, 2008 12:44 pm; edited 2 times in total |
|
| Back to top |
|
|
tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
|
| Posted: Wed Jun 04, 2008 12:39 pm Post subject: |
|
|
For me it was a finned x-wing on <9>, then an xy-wing on <269> with pivot in r3c1 that did it in. Overall a fun one to do. 
Ted |
|
| Back to top |
|
|
tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
|
| Posted: Wed Jun 04, 2008 1:09 pm Post subject: |
|
|
I would appreciate some help on a condition which I noticed a short time ago and is also in this puzzle.
Looking at box 3, we see a strong link on <9> in row 1, and a second strong link on <9> in column <7>. It looks like a kite except we have another cell in box 3, r3c9, that also has a <9>. I look at this condition as a finned kite. Both strong links functions as a normal kite, causing the pincers r1c1 and r7c7, to eliminate the <9> in r7c1. In addition, if the finned cell is a <9>, then both pincers will become <9>. I used this technique to solve this puzzle (followed by an xy-wing on <269>).
Is this condition used by others? If so, does it have a common name?
Ted
| Code: |
+------------+---------+------------+
| 39 4 1 | 5 6 8 | 2 39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 69 1 689 |
+------------+---------+------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 29 29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+------------+---------+------------+
| 269 1 4 | 7 58 29 | 69 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269 |
| 7 25 3 | 6 58 29 | 1 4 289 |
+------------+---------+------------+
|
Play this puzzle online at the Daily Sudoku site[/quote] |
|
| Back to top |
|
|
Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
|
| Posted: Wed Jun 04, 2008 1:26 pm Post subject: |
|
|
For those who like an UR solution, the digits marked (+) in the 29 UR* reveals two pincer cells for digit <9>, which eliminates <9> in R3C7 and R8C8
sweeping the grid. R8C89=5 or 6, otherwise we have a 29 deadly pattern.
R8C8=5 => R7C8=8 => R2C8=3 => R1C8=9 (a)
R8C9=6 => R7C7=9 (b)
| Code: | +-------------------------+-------------------------+-------------------------+
| 39 4 1 | 5 6 8 | 2 a 3=9 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 6-[9] 1 689 |
+-------------------------+-------------------------+-------------------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 *29 *29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+-------------------------+-------------------------+-------------------------+
| 269 1 4 | 7 58 29 | 6=9 b 58 3 |
| 8 256 59 | 4 1 3 | 7 *2-[9]+5 *29+6 |
| 7 25 3 | 6 58 29 | 1 4 289 |
+-------------------------+-------------------------+-------------------------+ |
|
|
| Back to top |
|
|
stevieboy
Joined: 25 Jan 2008
Posts: 31
Location: Michigan
|
| Posted: Wed Jun 04, 2008 3:56 pm Post subject: |
|
|
Isn't the XYZ-Wing from <269> in R7C1, eliminating the <9> in R3C7 legitimate? I haven't heard anyone mention that; this is what I used to solve it (I must've been lucky, I guess!!)
| Code: |
+------------+---------+------------+
| 39 4 1 | 5 6 8 | 2 39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 6-9 1 689 |
+------------+---------+------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 29 29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+------------+---------+------------+
| 269 1 4 | 7 58 29 | 69 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269 |
| 7 25 3 | 6 58 29 | 1 4 289 |
+------------+---------+------------+
|
|
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Wed Jun 04, 2008 4:32 pm Post subject: |
|
|
...I've transferred my post from the June 4 VH one. I originally had it down as January 4. Sometimes it's hard to tell the difference in Canada.
Anyway.. I found two ER solutions using the two 9’s in C7 that get rid of the <9> in R3C3 (using Box7) or the <9> in R7C1 (using Box1).
Then I used the xy wing <269> to take out the <6> in R7C7. |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Wed Jun 04, 2008 4:46 pm Post subject: |
|
|
| stevieboy wrote: | Isn't the XYZ-Wing from <269> in R7C1, eliminating the <9> in R3C7 legitimate? I haven't heard anyone mention that; this is what I used to solve it (I must've been lucky, I guess!!)
| Code: |
+------------+---------+------------+
| 39 4 1 | 5 6 8 | 2 39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 6-9 1 689 |
+------------+---------+------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 29 29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+------------+---------+------------+
| 269 1 4 | 7 58 29 | 69 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269 |
| 7 25 3 | 6 58 29 | 1 4 289 |
+------------+---------+------------+
|
|
I can't see an XYZ-Wing based in r7c1. It appears that you're treating that cell as if were 26 and creating an XY-Wing. The essence of an XYZ-Wing is that candidates are eliminated that can see all three cells and r3c7 sees two. The XYZ and one of XZ or YZ have to be in the same box. |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Wed Jun 04, 2008 6:05 pm Post subject: |
|
|
Just to be quite clear what we are talking about: after basics,
| Code: |
+--------------------------+--------------------------+--------------------------+
| 39 4 1 | 5 6 8 | 2 39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
| 29 258 59 | 3 4 7 | 69 1 689 |
+--------------------------+--------------------------+--------------------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 29 29* |
| 1 9 2 | 8 3 6 | 5 7 4 |
+--------------------------+--------------------------+--------------------------+
| 269 1 4 | 7 58 29 | 69* 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269* |
| 7 25 3 | 6 58 29 | 1 4 28-9 |
+--------------------------+--------------------------+--------------------------+
|
there is an xyz-wing consisting of cells r5c9 (29), r8c9(269) and r7c7 (69).
Here's how the xyz-wing works:
if r5c9 is 9 then r9c9 cannot be 9
if r5c9 is 2, then r7c7 and r8c9 form a naked pair (69) in box 9 and again r9c9 cannot be 9.
Later on, the 8 in r3c2 will be gone and we will have an xy-wing 58-25-28 in col 2 and row 9; it removes 8 from r3c9. |
|
| Back to top |
|
|
stevieboy
Joined: 25 Jan 2008
Posts: 31
Location: Michigan
|
| Posted: Wed Jun 04, 2008 6:45 pm Post subject: |
|
|
| Marty R. wrote: |
I can't see an XYZ-Wing based in r7c1. It appears that you're treating that cell as if were 26 and creating an XY-Wing. The essence of an XYZ-Wing is that candidates are eliminated that can see all three cells and r3c7 sees two. The XYZ and one of XZ or YZ have to be in the same box. |
I keep forgetting that concept! Thanks, Marty (and nataraj)... |
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Wed Jun 04, 2008 10:14 pm Post subject: |
|
|
| because the xyz-wing was in the bottom right corner of the grid, I had to stare for a bit longer. |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Wed Jun 04, 2008 10:51 pm Post subject: |
|
|
| storm_norm wrote: | | because the xyz-wing was in the bottom right corner of the grid, I had to stare for a bit longer. |
Me too.
Actually, I only saw the xyz when I tried to re-create the position for posting.
When I did it on P&P i kept looking at the many 29 cells, trying to find something like a w-wing, when I hit on a useless w-wing (29 r5c8 and r9c6 connected via 39-39 in row 1) which I transported to r5c8 on one end and via r7c1 (269) - r7c6 to r9c6 on the other end.
"useless" w-wing says at least one of r5c8/r3c1 must be 2
tranport then says at least one of r9c6/r5c9 must be 9
This way I eliminated 9 from r9c9, just like the xyz-wing did.
Of course the xyz is much easier to describe ... :P |
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Wed Jun 04, 2008 10:57 pm Post subject: |
|
|
| Quote: | "useless" w-wing says at least one of r5c8/r3c1 must be 2
tranport then says at least one of r9c6/r5c9 must be 9 |
\
or as Asellus would call it. coloring via medusa bridge, and eliminating the 9 through a medusa multicoloring trap. |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Wed Jun 04, 2008 10:59 pm Post subject: |
|
|
| storm_norm wrote: | | Quote: | "useless" w-wing says at least one of r5c8/r3c1 must be 2
tranport then says at least one of r9c6/r5c9 must be 9 |
\
or as Asellus would call it. coloring via medusa bridge, and eliminating the 9 through a medusa multicoloring trap. |
no, no!
no Medusa at all
edit: at least none that I am aware of *blush*
edit the edit: but it might as well be. I am notoriously bad at remembering the proper names for some techniques. The different UR types, for example. The different names for straightforward coloring (like kite etc.),...
I mostly remember the basic principle and apply it. Which gets me into trouble sometimes, calling a w-wing a semi-remote pair or something of that sort ...
So maybe it was a Medusa trap wrap after all 
And while I'm at it, might as well propose a NEW NAME (ta daa):
common name for x-wing, skyscraper, kite, turbot fish: NUNCHUCK
two rods (the strong links, made of wood I think) connected by a chain (the weak link). Every cell that gets into contact with the two buiness ends of the nunchuck loses a candidate.
Hashime.
Last edited by nataraj on Wed Jun 04, 2008 11:25 pm; edited 2 times in total |
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Wed Jun 04, 2008 11:20 pm Post subject: |
|
|
| Code: | +--------------------------+--------------------------+--------------------------+
|*39 4 1 | 5 6 8 | 2 *39 7 |
| 36 68 7 | 2 9 1 | 4 38 5 |
|#29 258 59 | 3 4 7 | 69 1 689 |
+--------------------------+--------------------------+--------------------------+
| 5 7 8 | 9 2 4 | 3 6 1 |
| 4 3 6 | 1 7 5 | 8 #29 #29 |
| 1 9 2 | 8 3 6 | 5 7 4 |
+--------------------------+--------------------------+--------------------------+
|#269 1 4 | 7 58 #29 | 69 58 3 |
| 8 256 59 | 4 1 3 | 7 259 269 |
| 7 25 3 | 6 58 #29 | 1 4 289 |
+--------------------------+--------------------------+--------------------------+ |
above is marked the nataraj useless w-wing extended to the {2,9} pairs in r9c6 and r5c9, and is a nice find.
in notation is...
(9=2)r9c6-(2)r7c6=(2)r7c1-(2=9)r3c1-(9)r1c1=(9)r1c8-(9=2)r5c8-(2=9)r5c9; r9c9<>9
visually...
the green lines are the useless w-wing... the blue lines are the extended coloring which makes the 9's the pincers to eliminate the 9 in r9c9 |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Wed Jun 04, 2008 11:28 pm Post subject: |
|
|
| Norm, I love your colorful visuals! |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
