| View previous topic :: View next topic |
| Author |
Message |
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
 Posted: Fri Aug 10, 2007 1:58 pm Post subject: 10 Aug VH |
 |
|
| Can I be first. I needed an xy wing with a 43 pivot on R5C6 (which gets rid of 9 in R3C9. Then a skyscraper on 9s in Cols 6 & 7. (gets rid of 9 in R3C8). Not sure that step was necessary. |
|
| Back to top |
|
 |
sdq_pete
Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL
|
| Posted: Fri Aug 10, 2007 3:30 pm Post subject: |
|
|
I can't quite relate that to the position I reached, which was the following:
| Code: |
+---------+----------+------------+
| 2 5 6 | 4 19 7 | 19 3 8 |
| 3 9 48 | 18 2 6 | 14 7 5 |
| 1 7 48 | 38 5 39 | 2 469 46 |
+---------+----------+------------+
| 4 8 9 | 2 36 5 | 36 1 7 |
| 5 6 1 | 7 8 34 | 34 2 9 |
| 7 2 3 | 9 46 1 | 8 5 46 |
+---------+----------+------------+
| 69 3 2 | 5 7 49 | 469 8 1 |
| 8 1 7 | 6 49 2 | 5 49 3 |
| 69 4 5 | 13 13 8 | 7 69 2 |
+---------+----------+------------+
|
Play this puzzle online at the Daily Sudoku site
I unlocked this position with a slightly unorthodox application of an XYZ wing. Note the XYZ-wing with pivot at R3C8 and pincers R3C9 and R8C8. There is no direct victim. However, either one of R3C8 and R3C9 is 4, or R8C8 is 4. Both lead easily to R7C6 = 4 and R8C5 = 9.
Peter |
|
| Back to top |
|
|
TKiel
Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI
|
| Posted: Fri Aug 10, 2007 4:24 pm Post subject: |
|
|
| The X-wing on 4 in R57 is a little cleaner. |
|
| Back to top |
|
|
cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
|
| Posted: Fri Aug 10, 2007 6:47 pm Post subject: |
|
|
Sdq. Pete: I couldn't see how you got the 9 in R5C9.
But anyway, with you "victimless xyz" thing, you still seem to end up with 2 trial and error assumptions. In this case I think it was a coincidence that they both worked. |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Sat Aug 11, 2007 4:33 am Post subject: |
|
|
I used the 34-39-49 XY-Wing to zap the 9 in r3c9, creating a strong link on 9 in row 3. That allowed a W-Wing on the 49s in r7c6 and r8c8, which solved r8c5=9, which finished the puzzle.
| Code: |
+---------+----------+------------+
| 2 5 6 | 4 19 7 | 19 3 8 |
| 3 9 48 | 18 2 6 | 14 7 5 |
| 1 7 48 | 38 5 39 | 2 469 46 |
+---------+----------+------------+
| 4 8 9 | 2 36 5 | 136 16 7 |
| 5 6 1 | 7 8 34 | 349 2 49 |
| 7 2 3 | 9 46 1 | 8 5 46 |
+---------+----------+------------+
| 69 3 2 | 5 7 49 | 469 8 1 |
| 8 1 7 | 6 49 2 | 5 49 3 |
| 69 4 5 | 13 13 8 | 7 69 2 |
+---------+----------+------------+
|
Play this puzzle online at the Daily Sudoku site |
|
| Back to top |
|
|
TKiel
Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI
|
| Posted: Sat Aug 11, 2007 2:07 pm Post subject: |
|
|
| From the position Marty posted, it's also possible to exclude <9> from three of the four tri-value cells (Marty's XY-wing does one), which turns it into a BUG+1. |
|
| Back to top |
|
|
keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
|
| Posted: Sat Aug 11, 2007 3:26 pm Post subject: |
|
|
| TKiel wrote: | | The X-wing on 4 in R57 is a little cleaner. |
In Marty's grid there is a swordfish in C589 which takes out <4> in R3C3, essentially the same elimination as the X-wing.
Keith |
|
| Back to top |
|
|
Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
|
| Posted: Sat Aug 11, 2007 10:43 pm Post subject: |
|
|
There was also a diffirent solution path, which I took after the xy-wing pivot in R5C6, that cgordon mentioned. I don't now why but I spot these xy-chains sometimes easier than an xy-wing. This one was an 9cell xy-chain, which eliminates <4> in R3C8, because of the pincer-effect from the two <4>'s in R3C9 and R3C3.
[46][64][46][63][34][49][93][38][84]
| Code: |
+---------+----------+------------+
| 2 5 6 | 4 19 7 | 19 3 8 |
| 3 9 48 | 18 2 6 | 14 7 5 |
| 1 7 I48|H38 5 G39| 2 -469 A46|
+---------+----------+------------+
| 4 8 9 | 2 D36 5 | 36 1 7 |
| 5 6 1 | 7 8 E34| 34 2 9 |
| 7 2 3 | 9 C46 1 | 8 5 B46|
+---------+----------+------------+
| 69 3 2 | 5 7 F49| 469 8 1 |
| 8 1 7 | 6 49 2 | 5 49 3 |
| 69 4 5 | 13 13 8 | 7 69 2 |
+---------+----------+------------+
|
|
|
| Back to top |
|
|
Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
|
| Posted: Mon Aug 13, 2007 10:42 pm Post subject: August 13 VH |
|
|
I found a number of hidden pairs and triplets, a few x-wings, and then the decisive move was an xy-wing anchored in R9C1 which made R3C4 a 9.
Earl |
|
| Back to top |
|
|
eddieg
Joined: 12 Jan 2006
Posts: 47
Location: San Diego, CA USA
|
| Posted: Wed Aug 15, 2007 3:21 pm Post subject: Now I get it. |
|
|
| Marty, Thanks for clarification on the XY-Wing that helped to eliminate the 9 in R3C9. I had a real obstacle to making the link (for some unkonwn) reason. My sanity is restored. |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
