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binxbolling
Joined: 02 Dec 2009
Posts: 1
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 Posted: Wed Dec 02, 2009 8:30 am Post subject: Please help, I'm losing my mind |
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I'd appreciate some help on how I'm supposed to proceed. I cannot figure out how to solve this. This is what I have so far:
I did this on my own, then used Sudoku Solver to figure out 1 more step. I won't tell you what it is to see if you can get it. Even after it pointed out what number is supposed to go where, I cannot for the life of me figure out WHY. I just don't see how you're supposed to get there. Any help is appreciated. |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Wed Dec 02, 2009 11:47 am Post subject: |
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Hello Binx,
First thing (and maybe the step you held back) is to look in (block 9) row 9 columns 8 and 9. There are 2 threes and they are the only 3s in the row. This means we eliminate the 3s that were in row 8 columns 7 and 8.
Once you've done that you have an X wing on 9s (in pink see below) this eliminates all the nines in blue.
That should get you on your way..........If you're not sure about xwings you can look them up in sudopedia.
Your step after this involves a pattern known as a 2 string kite or colouring if you prefer. That finishes the puzzle.
Let me know if you want a pic. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Wed Dec 02, 2009 6:33 pm Post subject: |
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| Code: |
+-----------+-------------+-------------+
| 6 28 1 | 2378 79 389 | 4 5 389 |
| 4 5 238 | 238 6 389 | 7 239 1 |
| 9 7 238 | 1 4 5 | 238 6 38 |
+-----------+-------------+-------------+
| 3 4 9 | 5 2 1 | 6 8 7 |
| 5 28 7 | 9 38 6 | 23 1 4 |
| 1 6 28 | 4 38 7 | 239 239 5 |
+-----------+-------------+-------------+
| 78 39 6 | 378 5 389 | 1 4 2 |
| 2 39 5 | 378 1 4 | 389 379 6 |
| 78 1 4 | 6 79 2 | 5 379 389 |
+-----------+-------------+-------------+
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Play this puzzle online at the Daily Sudoku site |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Wed Dec 02, 2009 6:56 pm Post subject: |
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Thanks Norm for the PM grid of the graphics!!!
It would have been nice if binxbolling had told us the elimination(s) offered by the solver he was using. That way, we would have known which technique he didn't understand. As it is, we're left with guessing -- pun based on a current thread in the Players' Forums.
*) Locked Candidate 2
*) X-Wing
*) Skyscraper/2-String Kite/turbot fish/Empty Rectangle/finned X-Wing |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Thu Dec 03, 2009 7:20 am Post subject: Re: Please help, I'm losing my mind |
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| binxbolling wrote: | I'd appreciate some help on how I'm supposed to proceed. I cannot figure out how to solve this. This is what I have so far:
I did this on my own, then used Sudoku Solver to figure out 1 more step. I won't tell you what it is to see if you can get it. |
You don't want an explanation for the step you don't understand?
There are many ways to solve every puzzle. Most of us won't use the step that you wonder about, whatever it is.
Simplest for me is to set r1c2 to 8. I would tell you why but you want secrets. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Dec 04, 2009 4:33 am Post subject: |
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| My move would be to set r5c2=2 ( which forces r1c2=8 ) to complete the puzzle. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Dec 04, 2009 4:57 am Post subject: |
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| tlanglet wrote: | | My move would be to set r5c2=2 ( which forces r1c2=8 ) to complete the puzzle. |
Which would presumably result as a consequence of the kite emanating from Box 1 or some other way? |
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Kdelle
Joined: 20 Mar 2008
Posts: 59
Location: Hudson, NH
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| Posted: Fri Dec 04, 2009 2:21 pm Post subject: |
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| Marty R. wrote: | | tlanglet wrote: | | My move would be to set r5c2=2 ( which forces r1c2=8 ) to complete the puzzle. |
Which would presumably result as a consequence of the kite emanating from Box 1 or some other way? |
Marty,
I don't see that kite.
Kathy |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Dec 04, 2009 3:40 pm Post subject: |
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| Marty R. wrote: | | tlanglet wrote: | | My move would be to set r5c2=2 ( which forces r1c2=8 ) to complete the puzzle. |
Which would presumably result as a consequence of the kite emanating from Box 1 or some other way? |
| Code: | +-----------+-------------+-------------+
| 6 @28 1 | 2378 79 389 | 4 5 389 |
| 4 5 238 | 238 6 389 | 7 239 1 |
| 9 7 #238 | 1 4 5 |#238 6 38 |
+-----------+-------------+-------------+
| 3 4 9 | 5 2 1 | 6 8 7 |
| 5 28 7 | 9 38 6 |a23 1 4 |
| 1 6 @28 | 4 38 7 |a239b239 5 |
+-----------+-------------+-------------+
| 78 39 6 | 378 5 389 | 1 4 2 |
| 2 39 5 | 378 1 4 | 389 379 6 |
| 78 1 4 | 6 79 2 | 5 379 389 |
+-----------+-------------+-------------+ |
W-wing 28 with pincers in r1c2 and r6c3 marked @ and an "interesting" strong link on 2 in row3 marked #.
(2)r3c3 - (2=8)r1c2,
(2)r3c3 - (2=8)r6c3, (this condition is not needed but is "interesting")
(2)r3c7 - (2) r56c7 = (2)r6c8 - (2=8)r6c3; see cells marked "a" & "b"
Thus, the strong link conditions on 2 are satisfied; r23c3<>8, r5c2<>8 resulting in r5c2=2.
Ted |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Dec 04, 2009 5:00 pm Post subject: |
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| Quote: | Marty,
I don't see that kite.
Kathy |
Kathy,
Look at the 2s in box 1. There is a strong link on 2 in column 2 and another in row 3. Both of the 2s in box 1 can't be true, therefore either r5c2 or r3c7 must be true. These pincers remove the 2 from r5c7.
Hope that's clear enough. |
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Kdelle
Joined: 20 Mar 2008
Posts: 59
Location: Hudson, NH
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| Posted: Fri Dec 04, 2009 6:39 pm Post subject: |
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| Marty R. wrote: | | Quote: | Marty,
I don't see that kite.
Kathy |
Kathy,
Look at the 2s in box 1. There is a strong link on 2 in column 2 and another in row 3. Both of the 2s in box 1 can't be true, therefore either r5c2 or r3c7 must be true. These pincers remove the 2 from r5c7.
Hope that's clear enough. |
Marty,
For some reason I thought that there the had to be a strong link on the 2s in box 1 for a kite.....But I see that isn't necessary for your elimination. Thanks.
Kathy |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri Dec 04, 2009 7:23 pm Post subject: |
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| tlanglet wrote: | | Marty R. wrote: | | tlanglet wrote: | | My move would be to set r5c2=2 ( which forces r1c2=8 ) to complete the puzzle. |
Which would presumably result as a consequence of the kite emanating from Box 1 or some other way? |
| Code: | +-----------+-------------+-------------+
| 6 @28 1 | 2378 79 389 | 4 5 389 |
| 4 5 238 | 238 6 389 | 7 239 1 |
| 9 7 #238 | 1 4 5 |#238 6 38 |
+-----------+-------------+-------------+
| 3 4 9 | 5 2 1 | 6 8 7 |
| 5 28 7 | 9 38 6 |a23 1 4 |
| 1 6 @28 | 4 38 7 |a239b239 5 |
+-----------+-------------+-------------+
| 78 39 6 | 378 5 389 | 1 4 2 |
| 2 39 5 | 378 1 4 | 389 379 6 |
| 78 1 4 | 6 79 2 | 5 379 389 |
+-----------+-------------+-------------+ |
W-wing 28 with pincers in r1c2 and r6c3 marked @ and an "interesting" strong link on 2 in row3 marked #.
(2)r3c3 - (2=8)r1c2,
(2)r3c3 - (2=8)r6c3, (this condition is not needed but is "interesting")
(2)r3c7 - (2) r56c7 = (2)r6c8 - (2=8)r6c3; see cells marked "a" & "b"
Thus, the strong link conditions on 2 are satisfied; r23c3<>8, r5c2<>8 resulting in r5c2=2.
Ted |
this is an example how extensions made on a pattern can sometimes overlap other patterns which also make eliminations.
in Ted's chain this can be seen.
(8=2)r1c2 - (2)r3c3 = (2)r3c7 - (2)r56c7 = (2)r6c8 - (2=8)r6c3
of course the chain says that the 8 in r1c2 and the 8 in r6c3 can't both be false... but it also contains the ER in red. this eliminates the 2 in r6c3 as well.
on a side note. question: lets say a xx in the Daily sudoku site puzzle generator happened to post this puzzle as a Very Hard. Would the majority of posters STILL call it a Very Hard? or would the xx puzzle be called a VH+ |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Dec 04, 2009 7:53 pm Post subject: |
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Norm,
While reviewing your comments regarding my post, I realized that coloring or a kite on 2 with pivot in box3 deletes the 2 in r6c3 and completes the puzzle without even completing basics.
I think a rating of "Very Hard" is the highest rating for this puzzle given the easy solution possible.
Ted |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Dec 04, 2009 8:53 pm Post subject: |
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| Quote: | | For some reason I thought that there the had to be a strong link on the 2s in box 1 for a kite.....But I see that isn't necessary for your elimination. Thanks. |
Kathy,
A kite is a simple form of multi-coloring (two chains). Had there been a strong link on the 2s in box 1, say the 2 was absent from r2c3, then simple coloring (one chain) could have established the same pincers; no kite necessary. |
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