| View previous topic :: View next topic |
| Author |
Message |
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
 Posted: Mon Jan 28, 2008 4:11 am Post subject: Jan 28 VH |
 |
|
This may be the toughest "Very Hard" puzzle ever!
Keith |
|
| Back to top |
|
 |
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Mon Jan 28, 2008 6:04 am Post subject: Re: Jan 28 VH |
|
|
| keith wrote: | This may be the toughest "Very Hard" puzzle ever!
Keith |
No argument there. Very few freebies at the start and much more than the usual number of polyvalue cells. I must've missed some moves, since I used techniques that aren't required for these. But it took me:
ER
Finned X-Wing
X-Wing
Type 1 UR
XY-Wing
XY-Wing
There were a couple of potential W-Wings, but I couldn't see any connecting strong links.
Definitely a VH VH. |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Mon Jan 28, 2008 7:23 am Post subject: |
|
|
Very tough, indeed!
coloring on 7 removedd 7 from r6c5 (don't know if that helped any)
xwing 8 that was the breaktrough (r69 c58)
but not done!
xy wing 57-78-58 removed 5 from r9c1
opens up another xy wing 15-14-45 removes 5 from r1c3
that's it.
There was another coloring on 7 removed 7 from r2c2 and r5c5 but I don't remember exactly when (before or after the xy wings?) or whether it was necessary or not.
Great puzzle |
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Mon Jan 28, 2008 9:08 am Post subject: |
|
|
there is one elimination on 7 via coloring before the x-wing on 8.
after the x-wing on 8, get rid of some box eliminations and a naked pair {5,7}
| Code: | 2 1357 56 | 156 167 8 | 4 136 9
147 179 46 | 2 3 179 | 5 16 8
15 1359 8 | 1456 1469 159 | 2 136 7
---------------------------------------------------------------------
9 57 1 | 38 57 6 | 38 2 4
8 6 2 | 134 147 17 | 37 9 5
57 4 3 | 9 58 2 | 6 78 1
---------------------------------------------------------------------
3 58 7 | 568 69 59 | 1 4 2
6 158 9 | 158 2 4 | 78 57 3
145 2 45 | 7 18 3 | 9 58 6 |
this grid is after the x-wing on 8 and after the box eliminations, the x-wing on 7 is in r14c25
but that doesn't solve it, its the aforementioned {578} and {145} xy-wings that kill it.
Last edited by storm_norm on Mon Jan 28, 2008 9:30 am; edited 3 times in total |
|
| Back to top |
|
|
andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
|
| Posted: Mon Jan 28, 2008 9:24 am Post subject: |
|
|
Hmm, I thought it was pretty straightforward, although it did keep going a bit!
An x-wing on 8, as already noted.
An xy on 5,7,8
And another xy on 1,4,5.
QED!
John |
|
| Back to top |
|
|
Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
|
| Posted: Mon Jan 28, 2008 2:31 pm Post subject: Jan 28 VH |
|
|
Lots of x-wings, xy-wings, even a skyscraper.
A fun puzzle worthy of a VH rating.
Earl |
|
| Back to top |
|
|
Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
|
| Posted: Mon Jan 28, 2008 3:58 pm Post subject: |
|
|
This one was indeed a VH rating, the advanced solving sequence I took is an ER on digit <7> in Box 2, takes out <7> in R6C5, then an x-wing <8> in R69C58,
after that an M-wing with the [58] pair in R7C2 and R9C8, eliminating <8> in R8C7 was the final step. |
|
| Back to top |
|
|
andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
|
| Posted: Mon Jan 28, 2008 5:38 pm Post subject: |
|
|
| Johan wrote: | This one was indeed a VH rating, the advanced solving sequence I took is an ER on digit <7> in Box 2, takes out <7> in R6C5, then an x-wing <8> in R69C58,
after that an M-wing with the [58] pair in R7C2 and R9C8, eliminating <8> in R8C7 was the final step. |
M-wing? Don't think I've met one of those. 
John |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Mon Jan 28, 2008 6:03 pm Post subject: |
|
|
| andras wrote: | | Johan wrote: | This one was indeed a VH rating, the advanced solving sequence I took is an ER on digit <7> in Box 2, takes out <7> in R6C5, then an x-wing <8> in R69C58,
after that an M-wing with the [58] pair in R7C2 and R9C8, eliminating <8> in R8C7 was the final step. |
M-wing? Don't think I've met one of those.
John |
John,
Try the third post in this thread. Good luck.
Marty
http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=2143 |
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Mon Jan 28, 2008 6:22 pm Post subject: |
|
|
| Quote: | | opens up another xy wing 15-14-45 removes 5 from r1c3 |
Dead easy at the startl: All I needed were one x-wing, two skyscrapers, one xyz-wing and an ER - but then it got difficult!! In fact I had to resort to the Off-F method (get the answer Off the Forum). Thanks Nataraj for that. Perhaps we need a V VH category or some other new acronym.
Last edited by cgordon on Mon Jan 28, 2008 11:32 pm; edited 1 time in total |
|
| Back to top |
|
|
sdq_pete
Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL
|
| Posted: Mon Jan 28, 2008 9:25 pm Post subject: |
|
|
Found myself curiously error-prone with this one, twice reaching an illogical position following the saved state after basic moves and thinking I must have made a mistake at that stage. Still, on following through carefully enough I got there with the following:
| Code: | X 8 R69
XY 578 R6C8 (eliminating 5 in R9C1), and
XY 145 R9C1 |
Peter |
|
| Back to top |
|
|
nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
|
| Posted: Mon Jan 28, 2008 9:36 pm Post subject: |
|
|
| cgordon wrote: | | but then it got difficult!! ... Thanks Nataraj for that. Perhaps we need a VVH category or some other new acronym. |
You're welcome - and as you made it to the last hurdle, I'm sure it would have been only a matter of time... 
The new category - how about "RH" real hard. Hm. What about "vh" then. UNreal hard? Nah, no good. "VrH" very-ER hard? aaarrrggghh!
"XH" ? and then ? XXH?
Actually, I'm quite happy with "vh" as it is. Simply says naked pairs and box/line are not enough. Could do with a little variety sometimes, like vh not solvable by xwing and/or xyz wing, maybe throw in a swordfish or required w-wing at times but come on let's not get picky: we've waited long enough for a "vh" and we were rewarded. |
|
| Back to top |
|
|
eddieg
Joined: 12 Jan 2006
Posts: 47
Location: San Diego, CA USA
|
| Posted: Mon Jan 28, 2008 10:57 pm Post subject: Has anybody solved without coloring? |
|
|
| Looking for different solution. |
|
| Back to top |
|
|
sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
|
| Posted: Mon Jan 28, 2008 11:58 pm Post subject: 1/28 VH |
|
|
| can you tell me where the xy wing on the 14 45 15 is. i have the 14 and the 45 but the only possible 15 that i see that would eliminate the 5 in r1c3 is the 145 in r1c1. if this is a 15 not a 145 can you tell me how you eliminated the 4. thanks a bunch. |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Tue Jan 29, 2008 12:59 am Post subject: Re: 1/28 VH |
|
|
| sheryl wrote: | | can you tell me where the xy wing on the 14 45 15 is. i have the 14 and the 45 but the only possible 15 that i see that would eliminate the 5 in r1c3 is the 145 in r1c1. if this is a 15 not a 145 can you tell me how you eliminated the 4. thanks a bunch. |
Sheryl, this is the grid from Norm's post.
| Code: | 2 1357 56 | 156 167 8 | 4 136 9
147 179 46 | 2 3 179 | 5 16 8
15 1359 8 | 1456 1469 159 | 2 136 7
---------------------------------------------------------------------
9 57 1 | 38 57 6 | 38 2 4
8 6 2 | 134 147 17 | 37 9 5
57 4 3 | 9 58 2 | 6 78 1
---------------------------------------------------------------------
3 58 7 | 568 69 59 | 1 4 2
6 158 9 | 158 2 4 | 78 57 3
145 2 45 | 7 18 3 | 9 58 6 |
First, play the XY-Wing on 78-58-57 that's pivoted in r6c8. That gets rid of the 5 in r9c1. That cell now becomes the pivot for a 14-45-15 XY-Wing. |
|
| Back to top |
|
|
sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
|
| Posted: Tue Jan 29, 2008 1:04 am Post subject: today's vh |
|
|
marty,
i can't read the grid-- it's all squirrily. i don't see how you got rid of the 4 in r3c1(if indeed it's gone). can you explain. |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Tue Jan 29, 2008 1:22 am Post subject: Re: today's vh |
|
|
| sheryl wrote: | marty,
i can't read the grid-- it's all squirrily. i don't see how you got rid of the 4 in r3c1(if indeed it's gone). can you explain. |
Sheryl,
I deeply apologize, but I don't know what a squirrily grid looks like.  It's aligned properly as I look at it.
I also don't remember how I did the puzzle. But looking at Norm's grid, the only possibilities for 4 in row two are in box 1. Therefore, no 4s can exist in box 1 in rows 1 and 3.
Hope that helps.
Last edited by Marty R. on Tue Jan 29, 2008 2:03 am; edited 1 time in total |
|
| Back to top |
|
|
sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
|
| Posted: Tue Jan 29, 2008 1:27 am Post subject: today's vh |
|
|
marty,
sorry, i just didn't see it. but now i do see the elimination of the 4 in r3c1. and that finally solved it for me.
thanks for posting all the info. it indeed was a very hard VH! |
|
| Back to top |
|
|
sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
|
| Posted: Tue Jan 29, 2008 1:46 am Post subject: today's vh |
|
|
marty,
when i see norm's grid, row 1 is on 2 lines, row 2 is on 2 lines, etc. etc. therefore to me it looks all "squirrelly" and makes it hard to read. If it looks right to you, any ideas why mine would look different? |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Tue Jan 29, 2008 4:46 am Post subject: Re: today's vh |
|
|
| sheryl wrote: | marty,
when i see norm's grid, row 1 is on 2 lines, row 2 is on 2 lines, etc. etc. therefore to me it looks all "squirrelly" and makes it hard to read. If it looks right to you, any ideas why mine would look different? |
No idea. Does it happen with all the grids or just this one? However, if you answer that I wouldn't know what to say anyways. |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
