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mtharp
Joined: 19 Jun 2006
Posts: 30
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 Posted: Sat Feb 10, 2018 2:49 pm Post subject: chicago tribune 2/9/18 DS too hard |
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Folks, I am stuck again. Any pattern help appreciated.
Mike
| Code: |
+--------------+-----------------+---------------+
| 56 1 2579 | 457 4567 47 | 24679 8 3 |
| 4 2378 2578 | 9 5678 378 | 267 27 1 |
| 36 378 789 | 3478 1 2 | 4679 479 5 |
+--------------+-----------------+---------------+
| 9 48 3 | 478 2 478 | 5 1 6 |
| 1 248 248 | 6 3 5 | 478 47 9 |
| 7 5 6 | 48 9 1 | 248 3 24 |
+--------------+-----------------+---------------+
| 8 6 457 | 1 457 9 | 3 245 247 |
| 35 347 1457 | 2 457 6 | 149 459 8 |
| 2 9 1457 | 34578 4578 3478 | 14 6 47 |
+--------------+-----------------+---------------+
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Play this puzzle online at the Daily Sudoku site |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 10, 2018 4:48 pm Post subject: Re: chicago tribune 2/9/18 DS too hard |
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| mtharp wrote: | Folks, I am stuck again. Any pattern help appreciated.
Mike
| Code: |
+--------------+-----------------+---------------+
| 56 1 2579 | 457 4567 47 | 24679 8 3 |
| 4 2378 2578 | 9 5678 378 | 267 27 1 |
| 36 378 789 | 3478 1 2 | 4679 479 5 |
+--------------+-----------------+---------------+
| 9 48 3 | 478 2 478 | 5 1 6 |
| 1 248 248 | 6 3 5 | 478 47 9 |
| 7 5 6 | 48 9 1 | 248 3 24 |
+--------------+-----------------+---------------+
| 8 6 457 | 1 457 9 | 3 245 247 |
| 35 347 1457 | 2 457 6 | 149 459 8 |
| 2 9 1457 | 34578 4578 3478 | 14 6 47 |
+--------------+-----------------+---------------+
|
Play this puzzle online at the Daily Sudoku site |
There's a Skyscraper (5) in c14. It makes two eliminations, one of which is -5r9c3, after which there are locked candidates, with the 5s in r9 confined to b8. |
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ZeroAssoluto
Joined: 05 Feb 2017
Posts: 940
Location: Rimini, Italy
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| Posted: Sat Feb 10, 2018 5:02 pm Post subject: |
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Hi Mike,
first step: pair 2,9 in r1c37.
Later it becomes more complicated.
Eventually we resent for other steps.
Ciao Gianni |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 10, 2018 5:39 pm Post subject: |
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| ZeroAssoluto wrote: | Hi Mike,
first step: pair 2,9 in r1c37.
Later it becomes more complicated.
Eventually we resent for other steps.
Ciao Gianni |
I agree, but I'd have stated it differently. That doesn't mean I'm right, it's just personal preference. I never paid much attention to hidden pairs because for every hidden pair or triple there's a complementary subset. In this case it's a 4567 quad and that's how I would've stated it had I noticed (shame on me). |
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immpy
Joined: 06 May 2017
Posts: 571
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| Posted: Sat Feb 10, 2018 6:06 pm Post subject: |
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Yes, first thing was the hidden quad/pair in row 1. (29) (4567)
Then the skyscraper (5). Both of these were noted. Follow this with a good thorough rinsing for box/line eliminations. That helped me to arrive here:
| Code: |
+--------------+-------------+--------------+
| 56 1 29 | 47 56 47 | 29 8 3 |
| 4 2378 2578 | 9 568 378 | 267 27 1 |
| 36 378 789 | 378 1 2 | 4679 479 5 |
+--------------+-------------+--------------+
| 9 48 3 | 478 2 478 | 5 1 6 |
| 1 248 248 | 6 3 5 | 478 47 9 |
| 7 5 6 | 48 9 1 | 248 3 24 |
+--------------+-------------+--------------+
| 8 6 457 | 1 47 9 | 3 245 247 |
| 35 347 1457 | 2 47 6 | 149 459 8 |
| 2 9 147 | 358 58 38 | 14 6 47 |
+--------------+-------------+--------------+
|
Play this puzzle online at the Daily Sudoku site
I then noticed a UR (47) r14c46, with 8 as the extra candidate on the common side of r4. Thus r4c2<>8(=4) and r6c4<>8(=4). That should solve it quite nicely. These coordinates can also be played as an X-Wing on 7 which results in some good eliminations as well. r2c6<>7 and r3c4<>7.
cheers...immp |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 10, 2018 10:28 pm Post subject: |
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| Quote: | | I then noticed a UR (47) r14c46, with 8 as the extra candidate on the common side of r4 |
Yes, that's an example of a Type 2 UR. |
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mtharp
Joined: 19 Jun 2006
Posts: 30
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| Posted: Sun Feb 11, 2018 1:56 pm Post subject: |
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Folks, I appreciate the help.
Thanks.
Mike |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Sun Feb 11, 2018 11:21 pm Post subject: |
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Hi everyone
This scheme can be solved with just one step after basics using the technique de pistes de Robert Mauriès. The trace R1C3 = 2 is certainly false because it produces a contradiction. After elimination of the 2 in R1C3 the solution is easily reached.
Ciao a Tutti
Paolo |
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